Course of antibody production by the DIG-ELISA method in neonatally infected and juvenile infected rats after primary infection with Breinlia booliati (Filarioidea: Onchocercidae).

The course of antibody production in Wistar neonatal and juvenile rats after primary infection with Breinlia booliati was studied by the DIG-ELISA technique using filter papers impregnated with capillary blood drawn from the infected rat tails at 7, 14, 28, 60 and 90 days post infection. Sera of neonatally infected rats did not react with adult worm antigen until day 7 and the titers of antibody remained at very low levels for the next 7 days. There was little tendency to eliminate the filarial larvae during this time. The antibody levels then rose rapidly throughout the next fortnight and increased to a maximum at day 60 after which the titer leveled out at a constant high value until early patency at day 90. On the other hand, antibodies could be detected in sera of juvenile infected rats as early as day 7 and the levels of antibody rose markedly to a maximum at day 28. During the period from day 60 to day 90 at early patency, the antibodies declined gradually to lower levels. The humoral immune responses of 42 neonatally infected rats and 53 juvenile infected rats of 3 strains (Lewis, Wistar and Sprague Dawley) were tested against soluble B. booliati antigens from both female (1:50) and male (1:10) worm extracts by the DIG-ELISA method. Antibodies were detected in sera from all the microfilaremic and amicrofilaremic rats belonging to neonatally and juvenile infected groups. Sera of clean neonatal rats did not give a positive reaction zone.