immunology of infectious and parasitic diseases - XXXVII Congress ...

Effects of bioactive Cryptococcus neoformans mimotopes on vascular
endothelial growth fator, nitric oxide and chemokine production in vitro by
immune cells.
SILVA, P.R. (PG) 1,2 ; BOMBANA, H.S. (IC) 2 ; ARAÚJO, A.S. (PG) 2 ; NOGUEIRA,
M.R. (PG) 2 ; GARCIA, F.G. (PG) 2 ; OLIVEIRA, A.C.S. (PG) 2 ; SILVA-TEIXEIRA,
D.N. 2
1 2
Centro de Formação Especial/CEFORES-UFTM, Laboratório de
Imunobiologia e Pesquisa em Ativação Celular (LIPAC), Instituto de Ciências
da Saúde (ICS), Universidade Federal do Triângulo Mineiro (UFTM), Uberaba,
MG.
e-mail: silvateixeira@mednet.com.br
Key words: Cryptococcus neoformans, “phage display”, mimotopes, VEGF,
nitric oxide (NO).
Introduction and objectives: Cryptococcus neoformans infected patients
show an augmented permeability of blood-brain barrier, which contributes to
increase morbidity and mortality in cryptococcosis. C. neoformans access to
central nervous system (CNS) is facilitated by vasoactive mediators produced
by immune cells, such as nitric oxide (NO), vascular endothelial growth factor
(VEGF), some cytokines and chemokines. In the present work we investigated
the effects of C. neoformans mimetic peptides (mimotopes) obtained by “phage
display” on in vitro production of vasoactive mediators (VEGF, NO, IL-1b, CCL-
2 and CXCL-8) by human mononuclear cells (PBMC) and polymorphonuclear
leukocytes (PMN).
Methods: PBMC and PMN from healthy volunteers (n=12) were isolated by a
double density ficoll-hypaque gradient. Mimotopes were selected by “phage
display” with a monoclonal antibody (18b7 Mab) against C. neoformans
capsular glucoronoxylomanan (GXM). After a chemical synthesis, peptides
were validated by ELISA. A linear sequence peptide (PL), a conformational
peptide containing one disulfide bridge (PC) and a double conformational
peptide (PD), made of two PC peptides linked by a GGGS spacer sequence,
were used to stimulate cells in vitro. VEGF, IL-1b, CCL-2 and CXCL-8