The characterization of T cell reactivities that are prone to down-mod
ulation by filarial parasites is central to understanding how these ne
matodes can survive for long periods of time within their human host a
nd to design appropriate immunoprophylactic measures, In the present s
tudy, TCRBV gene usage was analyzed in response to filarial antigens b
y PCR using a panel of TCRBV gene segment family-specific oligonucleot
ide primers, Analysis of individuals highly responsive to Brugia malay
i adult worm antigen (BmA) (n = 4) indicated that following stimulatio
n with BmA a maximum of four TCRBV gene families were over-represented
in each subject. Those were TCRBV2, 9, 19 and 23 in subject 1; TCRBV8
, 9 and 16 in subject 2; TCRBV2, 8, 9 and 11 in subject 3; and TCRBV13
and 23 in subject 4, The analysis of one subject who was unresponsive
to BmA before but regained responsiveness after diethylcarbamazine tr
eatment revealed that there was no. overexpression of a particular TCR
BV gene family before chemotherapy, whereas after chemotherapy three T
CRBV gene families (TCRBV8, 16 and 19) were found to be overexpressed.
Complementarity determining region 3 size analysis of a selection of
the overexpressed TCRBV genes displayed oligoclonality in some of the
observed expansions, Together these observations show that limited T c
ell subpopulations are clonally amplified in BmA-stimulated peripheral
blood mononuclear cells of filarial responder subjects, possibly driv
en by a restricted number of antigens.