Trypanosoma cruzi-Induced Suppression of the Primary Immune Response in Murine Cell Cultures to T-Cell-Dependent and -Independent Antigens

Abstract

In vitro antisheep erythrocyte (SRBC) and antitrinitrophenyl (TNP) antibody responses of spleen cells obtained from C57BL/6 mice infected with Trypanosoma cruzi were reduced as early as 6 days postinfection and not detectable after 18 days of infection. Lymph node cells had normal antibody responses to SRBC and TNP in vitro until the 11th day of infection, after which responses were diminished. By day 31 of infection, lymph node cells were unresponsive to both SRBC and TNP in vitro. Not only were the antibody responses of spleen and lympho node cells to T-cell-dependent and -independent antigens progressively reduced as the period of infection increased, but in addition, the effect of lymphoid cell density and antigen dose on antibody production underwent several sequential changes. As the infection advanced, low densities of cultured lymphoid cells and low doses of antigen were ineffective in eliciting a detectable immune response, whereas high densities of lymphoid cells and high doses of antigen resulted in responses approximately equivalent to that observed with normal cells under the same conditions. Results of cell mixing studies have shown that a plastic-adherent, macrophage-like cell plays a major role in the suppressed humoral responses observed in this host-parasite system.

Immune Response to Giardia duodenalis

“…Protozoan and metazoan parasites have the ability to depress the immune response of their host to heterologous antigens (49,63,179). Giardia trophozoites have been associated with immunodepression in response to heterologous antigens.…”

Giardia muris‐induced depression of the primary immune response in spleen and mesenteric lymph node cell cultures to sheep red blood cells

“…Our results indicate that the suppressor activity was localized in plastic-adherent fraction of spleen cell populations isolated from both susceptible A/J and resistant BI0.A mice. Plasticadherent macrophage-like suppressor cells were shown to be the mediators of immunodepression in other flagellate infections such as T. cruzi (Cunningham & Kuhn 1980) and T. rhodesiense (Wellhousen & Mansfield 1979). It is interesting to note that cell subpopulation which is responsible for mediating immunodepression in infections of mice with G. muris, an extracellular protozoan, has similar properties to the cell population which mediates immunodepression for intracellular organisms.…”

“…In this case, it is often quite impossible to study the mechanisms leading to immunodepression in parasitic infections without designing in uitro experiments to study the phenomenon. For example, the results M.Belosevic, G.M.Faubert & J.D.MacLean from in vitro studies have shown that macrophage-like suppressor cells play an important role in infections of mice with Trypanosoma cruzi (Cunningham & Kuhn 1980), Trypanosoma rhodesiense (Wellhousen & Mansfield 1979) and Toxoplasma (Suzuki & Kobayashi 1984). Recently, Suzuki & Kobayashi (1984) have identified suppressor macrophage subpopulation in mice infected with Toxoplasma which inhibits the proliferation of lymphocytes by direct contact with the responder target cells.…”

Initial induction of immunity, followed by suppression of responses to parasite antigens during Trypanosoma cruzi infection of mice

“…Infection with the protozoan parasite Trjpanosoma cruzi, as with many parasites, results in the establishment of an immunosuppressed state in the vertebrate host (Rowland & Kuhn 1978b, Cunningham & Kuhn 1980b, Reed, Larsen & Speer 1977, Krettli & Pereira 198 1, Camus et at. 1979.…”