Comparative Assessment of Antibodies to Circumsporozoite Protein [CSP/(NANP)40] and Ring Form Erythrocyte Surface Antigen (RESA/PF155) in Symptomatic and Asymptomatic P. falciparum Infections in Metropolitan Ibadan, Nigeria.

Abstract

Thirty four confirmed malaria (CM) patients and 38 individuals with asymptomatic P. falciparum parasitaemia (AP) were assessed for antibodies to repeat epitope of circumsporozoite protein CSP (NANP)40 and ring form erythrocyte surface antigen RESA/Pf155 in Ibadan, Nigeria. Of the 34 CM patients, 31 (91.2%) were positive for antibodies to CSP, while 31 (18.6%) of the AP individuals were positive. The mean titre for antibody to RESA/Pf155 by ELISA in patients with clinical and parasitologically confirmed infections and AP individuals were 2050 and 1616 respectively. There was statistically no significant difference between the number of patients with clinical manifestations of malaria that were positive for anti-csp antibody and those of asymptomatic individuals (X2 = 2.29 for 1d.f., P7 0.10). On the
other hand, the mean RESA antibody titre in malaria patients was higher than that in asymptomatic individuals, but the difference was not statistically significant. These results suggest that in malaria endemic areas, premunition may be enhanced by antibody to CSP rather than parasite densities.