Carl Lowenberger

Areas of interest

Our research focuses on the transmission of disease-causing organisms by insect vectors, and more specifically we look at the insect immune response to these parasites. The insect immune response is a germ-line encoded response that results in the production of an arsenal of immune peptides. This innate immune response is not based on antibody:antigen responses, but is more similar to the acute phase immune response in vertebrates. We work with two insect vectors; mosquitoes that transmit malaria and nematodes, and kissing bugs that transmit Chagas disease.

We study a malaria model using Aedes aegypti, the yellow fever mosquito, and Plasmodium gallinaceum, the causal agent for avian malaria, and Brugia malayi, the causal agent for human lymphatic filariasis. We also study the interactions between this insect and Dengue virus, as this is the most important vector of Dengue throughout the world. We have isolated several immune peptides from this insect that are used to protect the insect from harmful pathogens. The question arises as to why these peptides are not expressed in response to the presence of specific parasites as they migrate through several host tissues during their development. One goal is to characterize several of these peptides and determine if the lack of the immune response is caused by the parasites not being recognized as 'non-self', or whether the parasites inactivate the immune response.

Another model we use is the kissing bug, Rhodnius prolixus, the vector for Chagas disease in Latin America. Unlike the mosquito system the parasites, Trypanosoma cruzi, never leave the insect gut. Instead as the insect feeds it defecates and fecal material containing parasites gets rubbed into the feeding site. This is an inefficient- but effective means of transmission. We propose that this system has developed because the parasite is susceptible to the insect immune peptides expressed in the body cavity and this inefficient mode of transmission allows the parasite to contact with host immune responses.

Much of the work is laboratory related but opportunities exist for work in the field. We currently have collaborations with researchers in Mexico (National Institutes of Public Health), Guatemala (Universidad del Valle), Costa Rica, (U. of Costa Rica), Colombia (U. de Antioquia, U. del Valle, CIDEIM), France (IBMC, Strasbourg) and the Université de Lille, and the USA (Colorado State University, U. of Wisconsin).