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Jones, B D; Ghori, N; Falkow, S
doi: 10.1084/jem.180.1.15pmid: 8006579
Salmonella species are known to initiate infection of mammalian hosts by penetrating the intestinal epithelium of the small bowel. These bacteria preferentially interact with Peyer's patches which are collections of lymphoid follicles making up the gut-associated lymphoid tissue. We infected murine ligated intestinal loops with invasive and noninvasive Salmonella typhimurium strains for 30, 60, 120, and 180 min and examined the infected tissue by transmission electron microscopy. Within 30 min, we found that invasive S. typhimurium exclusively entered M cells found within the follicle-associated epithelium (FAE) of the Peyer's patches. Initially, interactions between invasive bacteria and enterocytes adjacent to the M cells were not found. Invasion of M cells was associated with the ability of the bacteria to invade tissue culture cells. S. typhimurium mutants, which were noninvasive for tissue culture cells, could not be found in ligated loops associated with M cells or enterocytes after incubations of 30, 60, 120, or 180 min. At 60 min, internalized invasive S. typhimurium were cytotoxic for the M cells. Destruction of an M cell formed a gap in the FAE which allowed organisms to invade enterocytes adjacent to the dead cell. Later in the infection process (120 and 180 min), the presence of bacteria beneath the FAE correlated with changes in the cytoarchitecture of the lymphoid follicle. In addition, replicating Salmonella began to enter both the apical and basolateral surfaces of enterocytes adjacent to infected M cells.
Kirberg, J; Baron, A; Jakob, S; Rolink, A; Karjalainen, K; von Boehmer, H
doi: 10.1084/jem.180.1.25pmid: 8006585
We describe mice that express a transgenic T cell receptor alpha/beta (TCR-alpha/beta) specific for peptide 111-119 from influenza hemagglutinin presented by I-Ed class II major histocompatibility complex (MHC) molecules. The transgenic TCR is expressed on CD4+8- as well as CD4-8+ mature T cells even in mice that are deficient in rearrangement or do not express endogenous TCR-alpha genes. The CD4-8+ T cells require I-Ed class II MHC molecules for positive selection and can be activated to proliferate and to kill by I-Ed molecules presenting the relevant peptide. Full maturation of these cells, however, also requires the presence of class I MHC molecules. The results are compatible with the notion that T cell maturation requires multiple receptor-ligand interactions and establish an exception to the rule that class II-restricted TCRs are exclusively expressed by mature CD4+8- cells.
Coulie, P G; Brichard, V; Van Pel, A; Wölfel, T; Schneider, J; Traversari, C; Mattei, S; De Plaen, E; Lurquin, C; Szikora, J P; Renauld, J C; Boon, T
doi: 10.1084/jem.180.1.35pmid: 8006593
It has been reported previously that antitumor cytolytic T lymphocyte (CTL) clones can be isolated from blood lymphocytes of HLA-A2 melanoma patients, after stimulation in vitro with autologous tumor cells, and that some of these CTL clones lyse most HLA-A2 melanomas. A first antigen recognized by such CTL clones was previously shown to be encoded by the tyrosinase gene. We report here the identification of another gene that also directs the expression of an antigen recognized on most melanomas by CTL clones that are restricted by HLA-A2. The gene, designated Melan-A, is unrelated to any known gene. It is 18 kb long and comprises five exons. Like the tyrosinase gene, it is expressed in most melanoma tumor samples and, among normal cells, only in melanocytes.
Amiri, P; Haak-Frendscho, M; Robbins, K; McKerrow, J H; Stewart, T; Jardieu, P
doi: 10.1084/jem.180.1.43pmid: 8006599
The immunoglobulin E (IgE) response is generally considered an essential component of the host defense against parasitic helminths such as Schistosoma mansoni. In contrast, work on antischistosome vaccines suggests that interferon gamma (IFN-gamma) is the critical immune mediator for vaccine-induced immunity to the parasite. In this study, the total IgE response to a primary S. mansoni infection was suppressed by anti-IgE treatment in both normal mice and in mice with defective IFN genes (gene knockout GKO). Reduction of the IgE response resulted in decreased worm burden and a decrease in the number of eggs produced per worm in both normal and GKO mice. Whereas anti-IgE treatment also resulted in reduced hepatosplenomegaly, granulomas around existing schistosome eggs showed normal cellularity. Serum interleukin 4 levels fell in response to the reduction in serum IgE as well. The data suggest that IgE plays a detrimental, rather than beneficial, role for the host in schistosomiasis. Furthermore, the absence of IFN-gamma was found to be of little consequence to the host-response to adults or eggs in a primary schistosome infection.
Bartolazzi, A; Peach, R; Aruffo, A; Stamenkovic, I
doi: 10.1084/jem.180.1.53pmid: 7516417
CD44 is implicated in the regulation of tumor growth and metastasis but the mechanism by which expression of different CD44 isoforms determines the rate of primary and secondary tumor growth remains unclear. In the present study we use a human melanoma transfected with wild-type and mutant forms of CD44 to determine which functional property of the CD44 molecule is critical in influencing tumor behavior. We show that expression of a wild-type CD44 isoform that binds hyaluronic acid augments the rapidity of tumor formation by melanoma cells in vivo, whereas expression of a CD44 mutant, which does not mediate cell attachment to hyaluronate, fails to do so. The importance of CD44-hyaluronate interaction in tumor development is underscored by the differential inhibitory effect of soluble wild-type and mutant CD44-Ig fusion proteins on melanoma growth in vivo. Whereas local administration of a mutant, nonhyaluronate binding, CD44-Ig fusion protein has no effect on subcutaneous melanoma growth in mice, infusion of wild-type CD44-Ig is shown to block tumor development. Taken together, these observations suggest that the tumor growth promoting property of CD44 is largely dependent on its ability to mediate cell attachment to hyaluronate.
Eklund, K K; Ghildyal, N; Austen, K F; Friend, D S; Schiller, V; Stevens, R L
doi: 10.1084/jem.180.1.67pmid: 8006601
The ear, skin, and purified serosal mast cells of WBB6F1/J-(+/+) (WB-(+/+)) and WCB6F1/J-(+/+) (WC-(+/+)) mice contain high steady-state levels of the transcripts that encode mouse mast cell protease (mMCP) 2, mMCP-4, mMCP-5, mMCP-6, and mouse mast cell carboxypeptidase A (mMC-CPA). In contrast, no mast cell protease transcripts are present in abundance in the ear and skin of WBB6F1/J-W/Wv (W/Wv) and WCB6F1/J-Sl/Sld (Sl/Sld) mice which are mast cell-deficient in vivo due to defects in their c-kit and c-kit ligand genes, respectively. We now report that the immature bone marrow-derived mast cells (mBMMC) obtained in vitro with recombinant interleukin 3 (rIL-3) or WEHI-3 cell conditioned medium from WB-(+/+), WC-(+/+), W/Wv, and Sl/Sld mice all contain high steady-state levels of the mMCP-2, mMCP-4, mMCP-5, mMCP-6, and mMC-CPA transcripts. As assessed immunohistochemically, mMCP-2 protein and mMCP-5 protein are also present in the granules of mBMMC from WB-(+/+), WC-(+/+), and W/Wv mice. That Sl/Sld and W/Wv mBMMC contain high steady-state levels of five granule protease transcripts expressed by the mature serosal, ear, and skin mast cells of their normal +/+ littermates suggests that c-kit-mediated signal transduction is not essential for inducing transcription of these protease genes. Because rIL-4 inhibits the rIL-10-induced expression of mMCP-1 and mMCP-2 in BALB/cJ mBMMC, the ability of rIL-4 to influence protease mRNA levels in WC-(+/+) mBMMC and W/Wv mBMMC was investigated. Although rIL-10 induced expression of the mMCP-1 transcript in WC-(+/+) and W/Wv mBMMC, rIL-4 was not able to suppress the steady-state levels of the mMCP-1 transcript or any other protease transcript in these cultured mast cells. Thus, not only do BALB/cJ mBMMC express fewer granule proteases than mBMMC from mast cell-deficient strains and their normal littermates but the subsequent induction of late-expressed proteases in BALB/cJ mBMMC is more tightly regulated by IL-3 and IL-4.
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