Litomosoides carinii infection in cotton-rats before and after treatment with diethylcarbamazine and suramin: evolution of free serum antigens.

Immunoelectrodiffusion was used to detect free serum antigens after treatment with diethylcarbamazine (DEC) and Suramin (S) in 30 cotton-rats infected with Litomosoides carinii. Precipitin lines between an antiserum produced by an adult worm extract and the test serum indicated the presence of free antigens in the serum. The number of precipitin lines was between one and 3. Before treatment only 13.3% of infected rats were positive compared with 83.7% after treatment. There was a difference in the delay before the appearance, the persistence and, possibly, the nature of antigens liberated by DEC and S treatment. With DEC release occurred earlier than with S and the antigens persisted for a shorter time. With combined DEC + S therapy the results were similar to those obtained with DEC and S used alone.