Lectin Histochemistry of Trachea and Lung of Healthy Turkeys ...

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Lectin Histochemistry of Trachea and Lung of Healthy Turkeys ( Meleagris gallopavo)
and Turkeys with
Pneumonia
M. R. Ackermann, N. F. Cheville and P. G. Detilleux
Vet Pathol 1991 28: 192
DOI: 10.1177/030098589102800302
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Vet Pathol 28:192-1 99 (199 1)
Lectin Histochemistry of Trachea and Lung of Healthy Turkeys
(Meleagris gallopavo) and Turkeys with Pneumonia
M. R. A CKERMANN, N. F. CHEVILLE, AND P. G. D ET ILLEUX
US Department of Agriculture, Agricultural Research Service,
National Animal Disease Center, Ames, IA
Abstract. Thirteen lectins were used to characterize lectin-binding specificity of glycoconjugates on sections
of formalin-fixed lung and trachea from seven normal turkeys, two turkeys with acute pneumonia, and two
turkeys with chronic pneumonia. Neuraminidase was used to digest sialic acid residues. One N-acetylgalactosarnine-binding
lectin and two N-acetylgalactosamine/galactose-binding lectins stained the apical membrane
and cytoplasm of multi focal cells that lined air atria and hyperplastic granular cells. Other lectins in these groups
stained ciliated cells of the trachea and bronchi and air capillary epithelial cells. Sialic acid residues were on
apical surfaces of ciliated and nonciliated tracheal and bronchial lining cells, air capillary epithelial cells, and
vascular endothelial cells. Mannose/glucose-bind ing lectins stained reticular and elastic fibers in the lamina
propria of trachea, primary and secondary bronchi , and the tunica adventitia of arteries and veins. By transmission
electron microscopy, colloidal gold-Arachis hypogaea (peanut agglutinin) labeled microvilli on the apical
surface of mature granular cells. The L-fucose-bindin g lectin, in addition to several other lectins, stained
nonspecifically in both trachea and lung. These studies show that granular cells that line air atria can be identified
with lectins of N-acetylglucosamine and N-acetylgalactosamine/galactose groups, and that apical surfaces of
epithelial cells and endothelial cells in the trachea and lung express terminal sialic acid residues.
Key words: Avian species; granular cells; lectins; peanut agglutinin; type II pneumocytes.
Gl ycoconjugates comprising th e glycocalyx of the
respiratory epithelium are essential to normal mucociliary
and respiratory function. Sugar residues ofglycoconjugates
can also serve as receptor sites for respiratory
pathogens.v'? Experimentally, fimbrial-mediated
attachment ofEscherichia coli. a respiratory pathogen
of poultry, to th e tracheal mucosa of chickens can be
blocked by D -mannose residues . 10 In turkeys, fimbriamediated
adherence of E. coli to the respiratory tract
epithelium has not been demonstrated.i->
for type I (D-mannose-binding) fimbriae ofE. coli, 2)
characterize lectin-binding affinities to specific cell
types, and 3) identify sialic acid residues. A panel of
lectins was used to stain trachea and lung from healthy
3-week-old turkeys, IS-day-old turkeys with acute
pneumonia, and IO-week-old turkeys with chronic
pneumonia an d granular cell hyperplasia. Sialic acid
residues were identified using neuramini dase enzyme
digestion.
Biochemical characterization of epithelial cell gly- Materials and Metho ds
coconjugates is generally difficult, since samples are Distal trachea and lung sections from seven (Nos. 1-7),
oft en contaminated with sloughed cells, bacteria, and Broad-Breasted White, 3-week-old turkeys were fixed in
rnucus.P Biotinylated lectins ha ve been used histo- 10% neutral buffered formalin and stained with hematoxylin
ch emically, therefore, to determine binding affinities and eosin, Verhoeff-van Gieson stain, Gomori's reticulum
to respiratory epithelial cells lining the trachea or lung stain, Masson's Trichrome stain, and 13 different biotinylof
the rat, mouse, hamster, human fetus, and the hu- ated lectins (Vector Laboratories, Burlingame, CA) using a
man adult.4,5,7, 15, 18.2 1,22,27 Studies of human fetal lung direct peroxidase technique (Table I). Briefly, serial (3 jlm)
ha ve demonstrated sialidation of alveolar lining cells sections were deparaffinized with xylene. Endogenous perduring
maturation. Normal and hyperplastic type II oxidase was quenched with absolute methanol containing
pn eumocytes isolated from lungs of adult human be- 0.6% H20 2 and 0.074% HC!. Sections were rinsed with distilled
water, a Tris solution containing 0.1 mM Ca' ' and
ings can be identified with a lectin, M ac/ura pomiferia Mg++, then I% bovine serum album in in the Tris solution,
agglutinin, which bi nds a type II cell-specific glyco- followed by a I-hour incubation with a lectin-Tris solution.
protein. v" Granular cells ofturkeys that are capable of Diamin obenzoic acid was used as a chromogen, and sections
hyperplasia and secrete surfactant may be analogous were counterstained with Harris' hematoxylin . The lowest
to typ e II cells of mammals.t--" concentration of each lectin that resulted in specific, defini-
This study was designed to I) identify adhesion sites tive staining was used for both trachea and lung sections.
192
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Table 1. The concentrations of the lectins used in thi s
study (Golstein and Peretz)."
Lectin
Glu cose/mannose group
Conavalia ensiformis
(Jack bean)
Lens culinaris
Pisum sativum
N-acetylglucosamine
group
Triticum vulgare
(Wheat germ )
Su ccinylat ed Triticum
vulgare
N-acetylga lactosaminel
galactose group
Glycin maximus
(Soyb ean agglutinin)
Sophora japonicum
Arachis hypogaea
(Peanut agglut inin)
Phaesolus vulgaris
(leukoagglutinin)
Ricinus com m unis J
Griffonia simplicifolia J
Phaesolus vulgaris
(erythroagglutinin)
L-fucose gro up
Ulex europeas I
Abbreviation
* Concentration used on tissue sections from IO-week-old poults.
Lectin Histochemistry of Turkey Lung 193
Con A 5.0
LCA 2.5
PEA 2.5
WGA 2.5
sWGA 2.5
SBA 2.5
Lectin Con-
centration
(ug/rnl)
SJA 5.0
PNA 2.5 ; 5.0*
PHA-L 2.5
RCA -I 1.25
BSL-I 50.0
PHA-E 50.0
U EA-I 50.0
Lectin-binding specificity was tested by mixing each lectin
with a 0.1 M solution of its inhibitory sugar for 20 minutes
before application, or by treating sect ions with I% sodium
periodate, for 10 m inutes, prior to labeling; both techniques
prevented staining. Several sections were incubated with Vibrio
cholera neuraminidase (NA , I U/ml [Sigma, St. Louis,
MOD for 18 hours at 37 C and then stained with Arachis
hypogaea (PNA) or Triti cum vulgare (WGA) for the detection
of sialic acid residues. Several sect ions were incubated with
galacto se oxidase (5 U/m !) for 18 hours at 25 C and stained
with PNA. Galactose oxidase oxidizes galacto se residues into
aldehyde s that are not bound by PN A.
To determine ifacut e inflammation altered lectin affinities,
the battery of lectins was also used on similarly prepared
sections of trachea and lung from two (Nos. 8, 9) 3-weekold
Broad-Breasted White turkeys experimentally ino culated
intratracheally with E. coli 0143:K*:H27. The battery of
lectins was also used on trachea and lung sections of two
(Nos. 10, II) 10-week-old Broad -Breasted White turkeys with
chronic pneumonia, caused by experimenta l infection with
Chlamydia psittaci, to determine ifhyperplasti c granular cells
sta ined simi larly to non -hyperplastic granular cells. Normal
areas oflung from turkeys with acute and chronic pneumonia
serve d as internal controls to compare staining patterns to
3-week-old hea lthy poults (Nos. 1-7).
Arachis hypogaea (PNA) conjugated with 15-nm colloidal
gold (Po lysciences, Inc. , Warrington, PA) was directly labeled
to lung tissue for transmission electron microscopy. Lung
sam ples 0.5 x 0.5 cm from four , 3-week-old, Broad-Breasted
White turkeys were fixed in 2.5% glutaraldehyde (pH 7.4)
for 4 hours and stored in 0.1 M cacodylate buffer (pH 7.4).
T he sam ples were rinsed in microtiter plate wells containing
0.2 M phosphate buffered saline with 1.0% bovine serum
albumin for 5 minutes and transferred to a solution ofgoldlabeled
PNA (34 fig/ml) for I hour, then washed three times
for 5 minutes with bovine serum albumin. Control tissues
were either processed without lectin or incubated with the
gold -lectin previous ly mixed with either 0.1 M N-acetylgalactosamine
or 0.1 M D-galactose. Tissues were post -fixed
in 1% osmium tetroxide (pH 7.4), embedded in EPON, and
thin sections were stained with lead citrate and uranyl acetate.
Thin sections were examined on a Philips electron microscop
e (Mahwah, NJ) .
Results
Each lectin-binding group (mannose-glucose , N-acetylglucosamine,
N-acetylgalactosamine/galactose, and
L-fucose) stained different areas of tissue , but most
lectins within a group stained similarly (Tables 2, 3).
No staining was present in lung or trachea when the
Table 2. Lectin histochemical staining ofcomponents of distal tracheas from seven, healthy, 3-week -old turkeys (Nos.
1-7).
D-mannose
Groups*
nAcGlc nAcGal NA
Con A LCA PEA WGA PHA-L RCA-I PNA NA/PNA
Lamina propria 7/7t 7/7 7/7 0:1: 0 2/7 0 0
Adventitia of blood vesse ls 7/7 7/7 7/7 0 0 0 0 0
Ciliated cells 0 0 0 5/7 0 0 0 7/7
Nonciliated cells 0 0 0 0 4/7 5/7 0 7/7
* Group abbreviations indicate: D-mannose group; nAcGlc = N-acetylglucosamine group; nAcGal = N-acetylgalactosamine group;
NA = neuraminidase (NA) treatment followed by staining with Arachis hypogaea (PNA).
t Indicates number of poults with specific staining/number tested.
:j: 0 = no specificstaining.
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194 Ackermann, Cheville, and Detilleux
Table 3. Lect in histochemical sta ining of co m po nents of lun gs from seven, healthy, 3-week-o ld turkeys.
Groups"
D-mannose nAcGIc nAcGal NA
Con A LCA PEA WGA sWGA SBA PNA PHA-L RCA-I NN PNA
Lami na propria of bronchi 7/7t 7/7 7/7 0:1: 0 0 0 0 0 0
Adventi tia of blood vessels 7/7 7/7 7/7 0 0 0 0 0 0 0
Ciliated bronch ial cells§ 0 0 0 6/7 0 0 0 2/7 1/7 7/7
Nonciliated bronchial cells§ 0 0 0 5/7 0 0 0 5/7 4/7 7/7
Air ca pillary epithelial cells 0 0 0 7/7 0 0 0 0 5/7 7/7
Air atria lining cells 0 0 0 7/7 7/7 7/7 7/7 7/7 7/7 7/7
Endo the lial cells 0 0 0 5/7 0 0 0 0 0 7/7
* Group abbreviation indicate: D-mannose group; nAcGIc = N-acetylglucosamine group; nAcGal = N-acetylgalactosamine group;
NA = neuramin idase (NA) treatment followed by staining with Arachis hypogaea (PNA).
t Indicates number of poults with specific staining/number of poults tested.
t 0 = no specific staining.
§ Primary and secondary bronchi only.
appropriate blocking sugar was preincubated with lectin
or in periodate-treated sections.
In healthy turkeys, the mannose/glucose-binding
lectins , Conavalia ensiformis (Con A), Lens culinaris
(LCA), and Pisum sativum (PEA) consistently (7/7 turkeys)
stained the lamina propria of the trachea and
pulmonary bronchi and the ad ventitia oflung and trachea
blood vessels (Fig. I). Th ese lectins also stained
small vacuoles in epithelial cells that lined trachea, but
failed to stain the apical membrane. Triticum vulgare
(WGA) inconsistently stained the apical membranes
of ciliated cells of the trachea (5/7 ), primary and secondary
bronchi (6/7), and capillary endothelial cells
(5/7), and consistently stained cells that lined air atria
and air capillary epithelial cells. In contrast, succinylated
Triticum vulgare (sWGA) stained only the apical
cytoplasm and surface of cells that line air atria and
did not stain tracheal cells.
Glycin maximus (SBA), Arachis hypogaea (PNA) ,
Phaesolus vulgaris (PHA-L), and R icinus communis I
(RCA-I) stained the apical surface ofcells that line air
atri a; in addition, PHA-L and RCA-I inconsistently
stained oth er cell types, i.e., PHA-L stained apical surfaces
of nonciliated cells of the trachea, and ciliated
and nonciliated cells of the primary and secondary
bronchi, while RCA-I stained apical surfaces of nonciliated
cells of the trachea, primary and secondary
bronchi, and air capilla ry epithelial cells. Staining of
air atria lining cells by both N-acetylglucosamin e (WGA
and sWGA) and N-acetylgalactosamine/galactose
(SBA, PNA, PHA-L, and RCA-I)-binding lectins was
discontinuous, i.e., multifocal, individual cells were
stained (Figs. 2, 3).
Following incubation with neuraminidase, PNA
consistently stained additional cell types. Th e apical
surfaces ofciliated and nonciliated tracheal and bronchial
cells, air capillary epithelial cells, and vascular
endothelial cells were all stain ed by PNA following
neuraminidase treatment (Figs. 4-6). No differences in
staining were seen in the cells that line air atria between
neuraminidase-PNA-stained sections and PNA-stained
sections. The WGA staining following neuraminidase
digestion was restri cted to air atria lining cells. Galactose
oxida se-treated sections inhibited PNA staining
both before and after neuraminidase.
Lungs from turkeys (Nos. 8, 9) experimentally infected
with E. coli had acute, marked focally-extensive
suppurative pneumonia. Lectin staining ofdegenerate
epithelial and adventitial fibers in lungs with acute
pneumonia was decreased in intensity and often pale
in areas of acute fibrinosuppurative inflammation. In
degenerate or necrotic cells, lectin staining was often
irregular, pale, or absent, and the cytoplasm ofadjacent
heterophils and macrophages often stained (Figs. 7, 8).
Areas of lung unassociated with acute inflammation
stained similarly in both turkeys and were also similar
to lungs of healthy poults. In normal areas of lung,
there was consistent staining (212) ofbronchial lamina
Fig. 1. Trac hea; healthy turkey. Peroxid ase stai ning ofPisum sativum (PEA) binding sites in the lamina propria. Harris'
hem at oxylin co unte rsta in.
Fig. 2. Lung; healthy turkey. Peroxid ase staining of Arachis hypogaea (PNA) binding sites of th e ap ical surface and
cyto plas m o f cells that line ai r atria trabecula. Note multifocal staining ofindividual cells. Harris' hem at oxylin counterstain .
Fig. 3. Lung; normal area , I O-week-o ld turkey. Peroxidase stai ni ng of Arachis hypogaea (PNA) binding sites ofmultiple
foci of cells lining air at ria . Harris' hematoxylin counterstain .
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Lectin Histochemistry of Turkey Lung 195
Fig. 4. Lung; healthy turkey. Peroxidase staining of Arachis hypogaea (PNA) binding sites following neuraminidase
digestion. There is diffuse staining of the cilia of cells lining the trachea, the apical portion of nonciliated cells, and the
surface of capillary endothelial cells. Harris' hematoxylin counterstain.
Fig. 5. Lung; healthy turkey. Arachis hypogaea (PNA) staining following neuraminidase digestion. There is diffuse
staining of the apical membrane of arterial endothelial cells. Harris' hematoxylin counterstain.
Fig. 6. Lung; healthy turkey. Peroxidase staining of Arachis hypogaea (PNA) binding sites following neuraminidase
digestion. The apical membrane of lymphoepithelial cells that cover the bronchus-associated lymphoid tissue are stained.
Note the thin follicular-associated epithelium at the dome apex. Harris' hematoxylin counterstain.
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196 Ackermann, Cheville, and Detilleux
-,
propria and vascular adventitia by Con A, PEA, and
LCA; ciliated bronchial cells, air capillary epithelial
cells, and endothelial cells with WGA; air atria cells
(212) with PNA, SBA, sWGA, and neuraminidase­
PNA. Inconsistent staining (112) was seen in nonciliated
bronchial cells with WGA, RCA-I, and in air capillary
epithelial cells with RCA-I. No differences in
staining pattern were seen in stained sections of trachea.
Consistent staining (212) of the lamina propria
was seen with Con A, PEA, and LCA. Ciliated and
nonciliated cells stained consistently with neuraminidase-PNA,
but inconsistently (112) with WGA, PHA­
L, and RCA-I.
Chlamydia-infected lungs (turkey Nos. 10, 11) were
characterized by a chronic, marked multifocal Iymphoplasmacytic
pneumonia with marked multifocal
hyperplasia of granular cells. In lungs of 10-week-old
turkeys with chronic pneumonia, lectin staining patterns
and neuraminidase-PNA staining patterns were
similar in normal areas of lungs (non-hyperplastic) to
the normaI3-week-old turkeys; however, consistent (2/
2) staining ofnoneiliated bronchial cells was seen with
WGA. There was multifocal staining ofcells that line
air atria using lectins sWGA, SBA, and PNA. The
apical cytoplasm and surface of hyperplastic granular
cells that lined air atria also stained with PNA, SBA,
and sWGA (Fig. 9). Tracheal sections ofthose turkeys
also stained similarly to 3-week-old poults; however,
there was consistent staining ofciliated cellswith WGA.
Verhoeff-van Gieson, Gomori's, and Masson Trichrome
stains highlighted areas with interstitial fibers,
e.g., lamina propria of the trachea and pulmonary
bronchi, the pleura, and the tunica adventitia of tracheal
and pulmonary arteries and veins were stained.
Ulex europeas (UEA-I), Phaesolus vulgaris (erythroagglutinin),
Sophorajaponicum (SJA), and Griffonia simplicifolia-i
(BSL-I) either did not stain or stained sec-
Fig. 7. Lung; turkey with acute pneumonia. Peroxidase
staining ofLens culinaris (LeA) binding sites. The indi vidual
fibers tunica adventitia ofa medium-sized pulmonary artery
are separated by edema. Lens culinaris staining of fibers in
the outer tunica adventitia is pale when compared with the
inner portions of the adventitial layer. Some of the heterophils
and macrophages in the peripheral infiltrates have
stained cytoplasm. Harris' hematoxylin counterstain.
Fig. 8. Lung; turkey with acute pneumonia. Peroxidase staining of Glycin maximus (SBA) binding sites. Air atria are
distended by numerous, closely-packed bacteria, along with sloughed cells and several heterophils. The cells lining air atria
are degenerate and some contain bacteria. Note the pale and haphazard staining of degenerate cells with Glycin maximus
(SBA). Harris' hematoxylin counterstain.
Fig. 9. Lung; turke y with chronic pneumonia. Peroxidase staining ofGlycin maximus (SBA) binding sites. Hyperplastic
cells, which are closely packed and cuboidal, line a distended air atrium. The apical cytoplasm and surface ofman y ofthese
cells are stained . The air atrium is filled with seroproteinaceous fluid and low numbers of macrophages, heterophils, and
lymphocytes. Harris' hematoxylin counterstain.
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Lectin H istochem istry of T urkey Lung 197
Fig. 10. Electro n micrograph. Lung; turkey. Colloida l gold part icles (15 nm in diam eter) conjugated to gold-Arachis
hypogaea (PN A) are adhered to the apical plasma membran e and micro villi of a granular cell. Note that the gold part icles
do not adhere to the whorled lam ella of surfactant (S) presen t in the airway lum en. Note osmiophilic inclusio n bod ies within
the granular cell cyto plasm (arrows). Bar = I !Lm.
Fig. II. Electron micrograp h. Lung; turkey. Th e ap ical portion of a nongranular cell. Th e cell is a sho rt di stan ce from
the granular cell shown in Fig. 10, and it lacks colloida l gold part icles on its apical plasma me mbrane. Trilaminar substa nce
(T LS) is within the cyto plas m. Bar = I !Lm.
tion s diffusely and nonspecifically at lectin
concentrations of 0.5, 2.5, 5.0, 25, and 50 Jig/m!. The
blocking sugars and periodate treatment inhibited all
staining in control sections.
With transmission electron microscopy, colloidal
gold-PNA conjugate labeled the plasma membrane of
microvilli extending from the apical surface ofgranular
cells. Th ese cells had abundant cytoplasm and contain
ed several osmiophilic inclusion bodies (Fig. 10).
Cells that were not labeled included immature granular
cells with scant amounts ofcytoplasm and few osmiophilic
inclusion bodies, nongranular cells, and air capillary
epithelial cells (Fig. II). In addition, the conjugate
did not label surfactant and trilaminar substance
that was within the airways.
Discussion
In thi s study, we were unabl e to identify epithelial
cells in the lung or trachea to which there was an affinity
for the D-mannose binding lectins Conavalia ensiformis
(Con A), Lens culinaris (LCA), or Pisum satiuum
(PEA). Lack of staining by Con A was especially surprising,
since this lectin can bind internal sugar residues
of glycoproteins.? Lack of epithelial cell staining
by these lectins may reflect the following: low numbers
ofD-mannose residues present in the apical surface of
these cells in turkeys; blocking of D-mannose or glu-
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cose residues by a complex, three dimensional conformation
ofthe glycoconjugates; and loss ofthese residues
during processing. Most glycolipids, for example,
are lost following routine processing, and decreas ed
lectin-binding affinities can be seen in paraffin-embedded
sections when compared with frozen sections. I ?
Low numbers of available mannose residues may explain
why adherence by Escherichia coli strains expressing
mannose-binding type I fimbria has not been
demonstrated in the turkey.l,IO,25
Staining of interstitial and lamina propria fibers by
lectins may indicate the presence of glycosylated collagen
or elastin. Elastic fibers and reticular fibers were
prominent with traditional histochemical stains and
were in identical locations to areas stained by these
lectins. Sugar residues on these structures may facilitate
interstitial invasion and lead to serosal spread of
E. coli that express type I, D-mannose-binding fimbriae.
There is evidence in this study that granular cells,
but not the nongranular cells, were stained by N-acetylgalactosamine/galactose
and N-acetylglucosaminebinding
lectins. 12 ,1 3,19 The affinity of several lectins to
hyperplastic atrial cells supports a granular cell-lectin
affinity. Since staining by three of the lectins (PNA ,
sWGA, and SBA) was restricted to cells that line air
atria and hyperplastic atrial cells, these lectin s may be

198 Ackermann, Cheville, and Detilleux
useful markers for avian granul ar cells. This is similar
to the use of Mac/ura pomifera agglutinin (MPA)
marker used for rat and human type II cells. Mac/ura
pomifera agglutinin (MPA) is in the N-a cetylgalactosam
ine/galactose group, as is Arachis hypogaea (PNA)
and Glycin maximus (SBA).
Lectins staining the apical surface of granular cells
probably bind the plasma membrane rath er than the
ove rlying surfactant. Th is was demonstrated for PNA
with the colloidal-gold-PNA conjugate. In addition,
the apical surface of air capillary epithelial cells are
also often covered by a thin layer ofsurfactant, 12, 13 but
of the six lectins (WGA, sWGA, SBA, PNA, PHA-L,
and RCA-I) that stained atrial cells (cells that secrete
surfactant), only two (WGA and RCA-I) stained the
apical surface of air capillary epithelial cells, Of these
two lectins, Triticum vulgare (WGA) may adhere to
sialic acid residues of the plasma membrane, while
Ricinus com munis I (RCA-I) staining was not seen in
all turkeys (5/7). Although much ofthe surfactant may
be lost with tissue processing, surfactant-like membranes
are retained in tissues processed for electron
microscop y and were seen in this study. Lectins may
also bind trilaminar substance, but thi s material was
not seen on transmission electro n microscopy sections
of IO-week-old turkeys, and was limited to occasional
air atria of 3-week-old turkeys (unpublished observations).
The PNA staining of neuraminidase-digested sections
indicates that respiratory lining cells and endothelial
cells express sialic acid residues, Neuraminidase
cleaves sialic acid residues and expose s penultimate
galactose residues that can be stained by PNA. Sialic
acid residues can then be determined by comparing
PNA staining before and after neuraminidase treatment.
Sialic acid residues may be an important receptor
for certain pathogens ofturkeys. For example, virulent
E. coli strains may adhere to sialic residues to
enter pneumocytes that line air capillaries, and Bordetella
avium binds sialic acid residues ofciliated tracheal
cells.1.3 Respiratory epithelia ofoth er species also
express sialic acid. These include tracheal mucous cells
in the rat and mouse, and alveolar cells of human fetal
lung. 8 ,22,23 The presence of sialic acid residues was confirmed
by similarity of staining patterns with WGA
and neuram inidase/PNA. The WGA can bind sialic
acid, but succinate residues on sWGA prevent thi s
lectin from binding sialic acid. Cells that stained with
WG A, but not sWGA, therefore, indicate the presence
of sialic acid. In addition , WGA following neuraminidase
treatment resulted in a stain ing pattern similar
to sWGA (succinylation inhibits binding of sWGA to
sialic acid). One exception to this staining pattern was
the lack ofstaining ofnonciliated tracheal cells by WGA
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and the consistent staining of these cells by PNA following
neuraminidase.
Interference of lectin staining by inflammation was
demonstrated in lungs with acute pneumonia. Th is was
likely due to the action of glycosidases and hydrol ases
present in acute inflammatory exudates. Altered lectin
staining patterns with neoplasia and inflammation have
also been reported in other studies. 5 ,7, 14,26
In thi s study, the lowest concentration oflectin that
resulted in specific, definiti ve staining was used. For
several lectins (UEA-I, PHA-L, SJA, and BSL-I), staining
specificity was poor regardless of the lectin concentration
used. Although Ulex europeae I (UEA-I )
stains human endothelial cells and can be used as a
marker to identify some ofthese cells in hemangiomas
and hemangiosarcomas of human beings and dogs, it
did not stain turkey endothelial cells. This lectin does
not stain the normal endothelial cells ofrodents, chickens,
or endothelial cells of canine skin, kidn ey, and
liver, and renal endothelial cells of chickens, quail, and
oth er animal species. 2 ,6, I I,20
Acknowledgements
The authors thank Dr. J. P. Tappe, Jr., for supplying certain
tissues, Dr. J. T. Meehan for help in developing lectin staining
procedures, and R. Kappmeyer for technical assista nce.
References
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2 Alroy J, Ucci AA, Pereira MEA: Lectins: histochemical
probes for specific carbohydrate residues. In: Diagn ostic
Immunohistochemi stry, vol. 2, ed. DeLellis RA, pp. 67.
Masson, Inc" New York, NY, 1984
3 Arp LH: Bacterial infection of mucosal surfaces: an
ove rview of cellular and molecular mechanisms , In: Virulence
Mechanisms of Bacterial Path ogens, ed. Roth JA,
pp. 17. American Society for Microbiology, Washington,
DC, 1988
4 Augustin-Voss HG, Smith CA, Lewis RM: Phenotypic
characterization of normal and neoplastic cani ne endothelial
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Ames, IA 500 I0 (USA).
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