The natural occurrence of circulating antibodies in populations of endemic malarious areas
Biswas, S.; Saxena, Q.B.; Roy, A.
Indian Journal of Malariology 27(3): 139-148
1990
ISSN/ISBN: 0367-8326 PMID: 2292317 Document Number: 348459
The humoral response to soluble antigen extracted from Plasmodium falciparum schizonts and merozoites was assessed in 744 blood samples collected from Delhi, Ghaziabad, Jabalpur and Shahjahanpur, India. Parasitological and immunological data were considered for assessment of antibody during natural infections at various seasons. The antibody response was measured by enzyme immunoassays. Overall antimalarial IgG levels had started increasing in individuals over 5 years of age, indicating that the rate of infection was high in the lower age groups. In most of the individuals with active infection, IgG and IgM levels were high. Positivity in IgM denoted the active transmission of malaria. Elevated levels of antigen specific IgA were observed in some cases. The presence of circulating immune complexes during acute infection is thought to show the failure of detection of circulating free antibodies in some individuals. The significance of the findings in relation to the serological status in individuals naturally exposed to malaria is discussed.