Research Programme - usaid

Table 1I.Results otfeeding
Animal
Ni
229
II .pakai- .n d nymphon hrte rem
State led
r tNlll 30
243 resulialil s
23l utcecpliblc i,
24! siiscejiiiptie .47
251, sis1epihlc " 43
Coniitrtl ra i t i
( "o rtnd r,,hb it
.
Iur lies dislphiccl. iull litcks liM
had moulted, to pick tip7.parva.The fail ore of 2/3 of the
susceptibles to become infected also cast serious doubts on
the infectivity of the ticks, and thus detracted from the
apparently favourable outcome with the tick-resist ant
cattle. There is,however, tit) doubt that we succceded in
rendering the group I cattle resistant, which confirrins our
findiniiethe ill li~ild that 11.illI('it s dlCchp -CistanoCe
tituile sIsssl" uid less taikCtikh (h,tid ti h\ ,t te1t)1
0,1IAN Ill IIAI ION AND (tARA(IFRISA I ION (11- ANI( d NS
I-t( )M SAI.IVARfY i.ANt)S, R t 'ROII(VI IVI- SYSI I M.
(itt ANt) tIAMt)IYNIt'lI it PAR IIAtH F I)
I I N,1I.I V I (KS 0 - R/II'I( TI.I ,/S. ,'#'ll It
Tlhe studies undertaken involved immunis,tion of animals
with crude antigen extracts derived from unfed, partially fed
or fully fed ticks. Initial information on protein components
oh R?. aippendicrlatis organs producing the antigens
responsible for the resistance response against ticks is
described in this summnary,.
Soditit doidecyl sulfate-polyacrylamide g,:l electrophorcsis
SI)S-PA( I-) :igure 0) relsolsedIt las,t 52 proIteit bands
detected by C(omssie Blue staining in the salivary glands,
42 in the reproductive system, 40 in the gut and 41 inthe
haemolymph. Itneah of these organs there were several
unenumerated indistinct hands. There also appears to be a
number of protein bands shared by all 4 tick tissue organs.
Although these protein hands may be of similar molecular
weight, they need not necessarily ave the same primary
structure and fuiction.
Immune-precipitation sttidies were performed using
antiserum from a rabbit previously immiunised with unfed
tick homogenate and with lyophilised homogenate of fully
fed female ticks. (Ticks feeding on this rabbit showed
reduced reproductive potential). The tick antigen extract
used was radiolabeLed with IsS methionine and 11S cystein.
The selected anti-tick serum immune-precipitated (in the
presence of Stap/hi'loco'cus aureao) 9-10 radiolabelled
proteins (Figure 7) as analveld by SI)S-l'A(.L The
molecular weights of these proteins were 180,000; 160,000;
140,000; 130,000; 98,000; 92,000; 88,000; 85,000; and 82,000
daltons. The pattern of the specifically immune precipitated
proteins was remarkably similar between the tick tissie
antigen extracts (Figure 7).
It is hypothesised from these results that the antigen
causing the reduced reproductive resI onse in ticks may be
u 11 l ,tSCe'ibt li' 'attle'1odltick-mmi
\1calI't
4I1ig) ( litijil restil,
i . no icci n IolaS lo
, 7 n., ilctuil; [I' .1--
7 -
? .
Crlr, I 10ti1,
uclll t'01
o i 'luc y
0 I fu i t % nI n1c cll 'iin sercm-soin% ci
X.S Io Ilnlslt l , no I i c- 'l l
l hd t I '0 [Lis2l
30
2 1
o', 75
I.d
) Iillpli
one o lthe recognized antigetis. Detailed studies ale bei,-g
carried out, characterising and isolating sufficien, quantitie,
ol native or subunit proteins for further i',imunisatioit
trials, using the gut as the selected otgait.
160,000 wthwi,
,92 500WM
67,0000
39000
25,800,
14,500- e
.W1
'15
A B C D "
i1 !
Figure 6. Electrophoretic anallsis of tick priteins derived from salt vary
glands (A), reproductive system (1), gut (C), and haemolymph (D) of
I-day fed female R. appendiculatus. Molecular weight marker proteins In
dallons areIndicated in themargin on tlie left of the gel: RNA plymerase,
160,000 and 39,000; phoslphorylase 'a'92,000; bovine serum albumin,
67,000; chymotrypslonogen, 25,800 and lysozyme 14,500.
.,
V