Chronic ethanol consumption results in immunodeficiency. Previous work with chronic ethanol-fed mice has shown reduced splenic weight and cellularity, including reduced numbers of CD8+ T cells. However, antigen-specific CD8+ and CD4+ T cell responses in chronic ethanol-fed mice have been studied relatively little. We have used an attenuated Listeria monocytogenes strain DPL 1942 (LM DeltaactA) to inoculate mice and subsequently used CD4+ and CD8+ immunodominant peptides of LM to measure the CD4+ and CD8+ T cell responses after chronic ethanol exposure. We found no major differences between control and ethanol-fed mice in the kinetics and persistence of antigen-specific CD4+ T cells in response to an immunodominant LM peptide, as measured by intracellular IFN-gamma staining. In contrast to CD4+ responses, three methods of in vitro antigen presentation indicated that the primary response of CD8+ T cells to several different epitopes was reduced significantly in mice chronically fed ethanol. Antigen-specific CD8+ T cells were also reduced in chronic ethanol-fed mice during the contraction phase of the primary response, and memory cells evaluated at 29 and 60 days after inoculation were reduced significantly. BrdU proliferation assays showed that in vivo proliferation of CD8+ T cells was reduced in ethanol-fed mice, and IL-2-dependent in vitro proliferation of naive CD8+ T cells was also reduced. In conclusion, these results suggest that antigen-specific CD4+ T cell responses to LM are affected little by chronic ethanol consumption; however, antigen-specific CD8+ T cell responses are reduced significantly, as are in vivo and in vitro proliferation. The reduction of antigen-specific CD8+ T cells may contribute strongly to the immunodeficiency caused by ethanol abuse.

Alcohol use by pregnant women is a significant public health issue despite well-described risks to the fetus including physical and intellectual growth retardation and malformations. Although clinical studies are limited, they suggest that in utero alcohol exposure also results in significant immune deficiencies in naive neonates. However, little is known about fetal alcohol exposure (FAE) effects on adult infections. Therefore, to determine the long-term effects of FAE on disease susceptibility and the adult immune system, we infected FAE adult mice with influenza virus. In this study, we demonstrate that mice exposed to ethanol during gestation and nursing exhibit enhanced disease severity as well as increased and sustained pulmonary viral titers following influenza virus infection. Secondary exposure to alcohol as an adult further exacerbates these effects. Moreover, we demonstrate that FAE mice have impaired adaptive immune responses, including decreased numbers of virus-specific pulmonary CD8 T cells, a decreased size and frequency of pulmonary B cell foci, and reduced production of influenza-specific Ab following influenza infection. Together, our results suggest that FAE induces significant and long-term defects in immunity and susceptibility to influenza virus infection and that FAE individuals could be at increased risk for severe and fatal respiratory infections.

Cure of leishmaniasis requires a type 1 immune response characterized by IFN‐γ production. Leishmania major infection leads to a type 2 response suppressing cure of susceptible BALB/c mice, and L. major causes an exacerbated type 2 response in mouse strains with a gene knockout (KO) such that they lack IL‐12p40 (IL‐12KO mice). In contrast, type 1 responses are inhibited by TGF‐β without Th2 cell expansion in BALB/c mice infected with L. chagasi. We questioned whether the type 2 or the TGF‐β response would dominate during L. chagasi infection of IL‐12KO mice. C57BL/6 mice developed self‐resolving L. chagasi infection with abundant IFN‐γ. In contrast, L. chagasi disease was exacerbated and IFN‐γ was low in IL‐12KO mice. Total TGF‐β was significantly higher in IL‐12KO than control C57BL/6 mice, but IL‐4 and IL‐10 levels were similar. TGF‐β was further augmented in IL‐12/IFN‐γ double‐KO mice. Thus, in contrast to L. major, the TGF‐β response was exacerbated whereas type 2 cells were not expanded during L. chagasi infection of IL‐12KO mice. We conclude that L. chagasi has an inherent propensity to elicit a prominent TGF‐β response that either suppresses, or is suppressed by, a type 1 response. We propose this be termed a "type 3" immune response, which can antagonize a type 1 response.

Mice provide a useful model for the study of immune deficiency caused by chronic alcohol abuse. Their suitability is related to several factors, including in particular the extensive knowledge base in the immunology of mice already existing in the literature. Specific modeling of the immunodeficiency of the chronic human alcoholic requires that ethanol must be administered to the model for a significant portion of its life span. In mice, it has proven to be necessary to administer ethanol daily for up to 32 wk or longer to observe all the immune abnormalities that occur in middle-aged alcoholic humans. Such time spans are problematic with many of the common protocols for ethanol administration. It has been shown by others and confirmed by our group that the most practical way of accomplishing such long protocols is by administering ethanol in water as the only choice of water. Details of management of the chronic ethanol mouse colony are described here that are necessary for the success of such studies, including methods for initiating ethanol administration, maintenance of barrier protection, monitoring weight gain, strain differences and fetal alcohol exposure.

Cellular immune mechanisms resulting in gamma interferon production are critical for protection against visceral leishmaniasis. Antigens stimulating T-cell responses are likely present in the intracellular amastigote form of the parasite, since this is the form found in a mammalian host. To identify T-cell antigens of Leishmania chagasi, the parasite causing South American visceral leishmaniasis, we used a double antibody-T-cell technique to screen an amastigote cDNA library. One cDNA selected (Lcr1) encodes an antigen that stimulated proliferation of splenic T lymphocytes from infected mice that were either resistant (C3H.HeJ) or susceptible (BALB/c) to L. chagasi infection. The Lcr1 cDNA contains four highly divergent 201-bp repeats homologous to the 204-bp repeat of a Trypanosoma cruzi flagellar antigen gene. Results are consistent with a single copy of the Lcr1 gene producing an mRNA of >10 kb and a protein of >200 kDa. Recombinant Lcr1, cloned adjacent to polyhistidine and purified on a nickel affinity column, stimulated gamma interferon but not interleukin-4 (IL-4), IL-5, or IL-10 secretion by T-cell-enriched splenocytes from either susceptible or resistant mice during L. chagasi infection. Immunization with Lcr1 partially protected BALB/c mice against challenge with L. chagasi, indicating the utility of the double screening approach in selecting relevant T-cell antigens.