Submitted to: Journal of Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/10/2003
Publication Date: 2/15/2004
Citation: Morimoto, M., Morimoto, M., Whitmire, J., Star, R., Urban Jr, J.F., Gause, W. 2004. Peripheral cd4 cells rapidly accumulate at the host: Parasite interface and express a polarized th2 memory response in situ. Journal of Immunology. 172:2424-2430 (2004). Interpretive Summary: Techniques to measure gene expression in cells within particular tissues have been limited by the requirement to isolate the cells of interest from mixed populations of irrelevant cells. A novel technique called Laser Capture Micro-dissection (LCM) has become commercially available to microscopically remove cells of interest from a section of tissue using membranes above the area of interest that are gently heated with a laser. The heat from the laser allows the cells to adhere to the membrane that can then be placed in extraction buffers to measure gene products from those particular cells. This technique was used with tissues from mice infected with a common gastrointestinal parasite. It was shown that the host response to infection developed very quickly at the site of infection and that the genes that were activated fit the general pattern that is seen much later in the infection when whole tissues are analysed. This method provides a basis for examining tissues from many different organs in experimental rodents, livestock and humans for detailed study of their response to infection. This model will have an impact on studies in many different laboratories by scientists that are interested in the genes that regulate protection against infectious diseases, and that study the nutrient requirements of these tissues during an infection. The work will benefit scientists in government, industry, and academic laboratories who need to know how to enhance immune responses to control infection.
Technical Abstract: Memory peripheral Th2 immune responses resulting in host protection are not well studied due to the lack of suitable models and the difficulty of assessing Th2 cytokine expression at sites of inflammation. We have examined the localized immune response elicited by parasitic larvae of an intestinal nematode parasite, Heligmosomoides polygyrus, which encysts and develops in the small intestine. Laser capture micro-dissection (LCM) was utilized to examine cytokine gene expression in micro-environments associated with parasitic larvae in situ. Immunohistological staining of the cysts revealed a novel architecture and cellular composition during early stages (day 4) of the memory response with granulocytes infiltrating the cyst, and CD4+, TCR alpha/beta+ T cells surrounding but not entering the cyst. Similar analyses of the primary response showed no localized increase in CD4+, TCR alpha/beta+ T cells, but a similar infiltration of granulocytes into the cyst. LCM analysis of cytokine gene expression revealed marked IL-4 and IL-13 elevations during the memory, but not the primary immune response, at 4 days after inoculation. Anti-CD4 mAb treatment partially inhibited IL-4 and IL-13 elevations inside and surrounding the cyst suggesting that CD4+ T cells were an important source of these cytokines. Taken together, these studies demonstrate that a strong peripheral mucosal memory Th2 response rapidly develops at the host:parasite interface.