Preliminary characterization of the inducible humoral factor in the American cockroach (Periplaneta americana).

Previous studies have defined an inducible humoral immune response in the American cockroach that demonstrates specificity and memory. In addition, the response is affected by the age and gender of the animal. Preliminary studies have been initiated to determine which of the protein components found in immune hemolymph might be responsible for mediating this activity. Comparisons between hemolymphs from immune and control animals, using SDS-PAGE gel analysis, revealed that there was a unique band generated in immune animals with an approximate MW of 162K. In addition, several other bands, with MWs of 220K, 115K, 102K, 95K, 80K and 77K, appear to be enhanced in immune hemolymph. The 240K, 220K and 115K bands were found only in females, and so have been temporarily excluded from further study because they were gender-dependent. When hemolymph samples were absorbed with HBT toxoid, the 162K band was no longer present in immune hemolymph, and the 115K, 102K, 95K and the 80/77K doublet were all greatly reduced as compared to controls. Analysis of supernatants from 24 hour cultures of cells from immune and BTS-injected animals, revealed that immune cells secreted the 162K, 102K, 95K and 80K bands. The 115K band was barely detectable, and the 77K band appeared to be missing. Thus, these studies have provided some valuable initial information that reduces the number of proteins that should be considered for further study as mediators of the roach inducible humoral response.