T Cell–dependent Immune Response in C1q-deficient Mice: Defective Interferon γ Production by Antigen-specific T Cells

The role of the classical complement pathway in humoral immune responses was investigated in gene-targeted C1q-deficient mice (C1qA−/−). Production of antigen-specific immunoglobulin (Ig)G2a and IgG3 in primary and secondary responses to T cell–dependent antigen was significantly reduced, whereas IgM, IgG1, and IgG2b responses were similar in control and C1qA−/− mice. Despite abnormal humoral responses, B cells from C1qA−/− mice proliferated normally to a number of stimuli in vitro. Immune complex localization to follicular dendritic cells within splenic follicles was lacking in C1qA−/− mice. The precursor frequency of antigen-specific T cells was similar in C1qA−/− and wild-type mice. However, analysis of cytokine production by primed T cells in response to keyhole limpet hemocyanin revealed a significant reduction in interferon-γ production in C1qA−/− mice compared with control mice, whereas interleukin 4 secretion was equivalent. These data suggest that the classical pathway of complement may influence the cytokine profile of antigen-specific T lymphocytes and the subsequent immune response

The effect of acquired microbial enzymes on assimilation efficiency in the common woodlouse, Tracheoniscus rathkei

The digestive tract of the common woodlouse, Tracheoniscus rathkei Brandt (Isopoda: Oniscoidea), contains digestive enzymes active against α-1,4-glucans, which are the chief storage polysaccharides of vascular plants, algae, fungi, and animals, and β-1,3-glucans, which are present in algae and fungi. Digestive tract extracts also exhibit significant activity toward xylan and carboxymethyl-cellulose but negligible activity toward microcrystalline cellulose, substrates representative of the major structural polysaccharides of vascular plants. Low activity was detected toward pectin, and no activity was detected toward chitin. Activity toward xylan is due in part to microbial enzymes acquired from the leaf litter which was the isopod's normal food. Although ingested microbial xylanases are stable and active in the gut fluid, they do not make a quantitatively significant contribution to the isopod's ability to assimilate the hemicellulosic component of its diet. However, the assimilation of carbon from labeled plant fiber is enhanced in isopods which have acquired a cellulase by ingestion of leaf litter amended with a commercial preparation of the cellulase complex from the fungus, Penicillium funiculosum . This result demonstrates the potential contribution of acquired enzymes to the digestion of plant fiber in terrestrial detritivores. We urge caution, however, in assigning an important digestive function to ingested enzymes on the basis of evidence that only indicates that such enzymes are present in the gut fluid without additional evidence that their presence results in an enhancement of digestive efficiency.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47763/1/442_2004_Article_BF00377057.pd

A Multicenter Randomized Clinical Trial Evaluating Interleukin-2 Activated Hematopoietic Stem Cell Transplantation and Post-transplant IL-2 for High Risk Breast Cancer Patients

This Phase III randomized multicenter trial compared progression-free (PFS) and overall survival (OS) for autologous peripheral blood stem cell (aPBSC) transplantation with or without immunotherapy in high-risk breast cancer patients.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44232/1/10549_2005_Article_4445.pd

Immune activation by T-independent antigens: lack of effect of macrophage depletion on the immune response to TNP-LPS, PVP and dextran.

Carrageenan, a sulphated polysaccharide, and rabbit anti-mouse macrophage serum, were used to inhibit macrophage function in BALB/c mice as well as to deplete macrophages from spleen cell cultures in an attempt to determine the requirement for macrophages in the immune response to several thymus-independent antigens. Carrageenan inhibited macrophage function and was cytotoxic at low concentrations. The ability of T and B lymphocytes to undergo mitogen-induced proliferation in the presence of PHA and PLS, respectively, was not affected by in vitro exposure of lymphoid cells to carrageenan. BALB/c mice injected with carrageenan demonstrated a suppressed immune response to SRBC, a thymus-dependent antigen, but not to E. coli LPS, polyvinyl-pyrrolidone or dextran B-1355S, all of which are known to be thymus independent antigens. The sensitivity of the in vivo immune response to SRBC after depletion of macrophages by carrageenan treatment was confirmed in vitro using the Marbrook--Diener culture system. The in vitro immune response to TNP-LPS was unaffected by either carrageenan treatment or treatment of BALB/c spleen cells with AMS and complement. The results of experiments which utilized the two anti-macrophage reagents, carrageenan and AMS, both in vivo and in vitro systems, suggest that the immune response to thymus-independent antigens does not require the participation of macrophages