Biological Transmission of Bacteria Inhibit By Hemolymph Lectins of American Cockroach

Background: although cockroaches are mechanical vector of many pathogens, still biological transmission of pathogensvia these insects is controversial. more covenant immune defense in the hemolymph of cockroaches may take this advantageto block any adaptation of pathogens regarding to biological transmission. lectin molecules in hemolymph of insectsplay as mediators of nonself recognition, in the innate immune response.methods: initially, lectin-carbohydrate interactions in hemolymph of american cockroach, periplaneta, americana, havebeen investigated and then as a model, non pathogenic soil bacterium, streptomyces griseus was used to specify the cockroachhemolymph reaction.results: the results showed that the hemolymph lectin activities were inhibited with glcnac, galactose, mannose, arabinose,and fucose but not with fructose, lactose and glucose. also, s. griseus cells were agglutinated with the cockroachhemolymph while in the presence of fructose, mannose and galactose, the agglutinin activities were inhibited. introducingthe soil bacterium, s. griseus, into the hemolymph increased both the lectin activities as well as the number of hemocytesfrom an average 101 to 2688 cells per milliliter hemolymph 6 days after injection. at the same time, the number of prohemocytesin the hemolymph declined while the granular cell numbers rapidly increased.conclusion: generally injecting s. griseus into the cockroach body resulted in a positive correlation between an increase inhemolymph titers and enhancement of hemocyte numbers. the results tentatively support the idea that soluble and/or cellassociatedlectins may be involved in immuno-recognition in insects and block biological transmission of pathogens.