Abstract:
Study of naturally acquired antibody responses to a potential vaccrne
candidate ts rmperatrve to provide insights to vaccine deve opment.
Recombinant protein PvRll, a putative vaccine candrdate representrng
regron ll of native Plasmodrum vivaxDlffy Bindrng Protein (DBP), was used
in ELISA to examine the total (lgG+tgM), igM and tgG isotype antibody
responses A reductlon sensiiive ELISA was preformed for toial antrbocjies.
Se:-a were collected from acute vivax malaria patients from two endemic
areas (EAs) ,rvhere low and unstable malaria conditions prevail, and fronr
a non-endemic area (NEA) in Sri Lanka. Pre,yalence of totai antibodies
was 50% from Colombo (NEA; N=111),46% from Anuradhapura (EA;
N=94) and 41ok fron Kataragarna (EA, N=106) Significantly higher
prevaience (Chi square, P<0 05) and magnitude (ANOVA, P<0 0't ) of tota
antibodies were recorded from NEA compared with E,As. Total antibody
parameters rn all test populatrons,,vere independent of aEe of indivrduals,
parasite density and previous exposure. Conformation sensitrve anti-pvRll
nronoclonai antibody 2H 1 0 reacted only w th non-reduced pvRil but not
with its reduced form. Test sera partially reacted with i'educed PvR1l, and
this indicating the recognition of irnear B cell eprtopes. A parailr.l increase
in total anlibody response to PvRll linear epitopes wrth rncreasrng e\pcsure
v.ras detected n residents of Kataragama. No signrficant difference was
detected arnong test populatrons either in anti-PvRli lgM prelavence (Cht
square. P>0.05) or magnitude (ANOVA, P>0.05). Prevalence of 19G3 (Chi
