ABSTRACT
The study was conducted on sera samples of 92 subjects from malaria endemic areas. All 92 subjects have experienced either previous or present infection with different parasitaemia levels of Plasmodium falciparum. The relationship between frequency of malaria infection, parasite densities and immunofluorescence malaria antibody titres of P. falciparum were studied. There was no significant correlation between IFA titres and parasitaemia levels or frequency of malarial infection. The serum inhibition to invasion of P. falciparum merozoites in vitro was found to vary according to the sera obtained from subjects with various malarial immune status. Parasite inhibitory antibody was not evident in sera from acutely infected subjects but was significantly observed in sera from convalescent subjects with an inhibition of P.falciparum merozoite invasion up to 85 per cent.