Murine monoclonal antibodies (mAb) of IgM and IgG subclasses that do not bind to canine cells have been used to detect the expression of Fc receptors on canine peripheral blood mononuclear cells and the cell line MAXEY-DH82. Murine Ig of IgG2a and IgG3 isotypes bound specifically to canine peripheral blood monocytes and to MAXEY-DH82, whereas Ig of IgG1, IgG2b, and IgM did not. No other cell types, including resting and activated peripheral blood lymphocytes, expressed this canine Fc receptor (cFcR) specific for murine IgG2a and IgG3. MAXEY-DH82 was used to characterize this Fc gamma 2a/gamma 3 receptor. Binding of murine IgG2a and IgG3 is trypsin sensitive and partially suppressed by phosphatidyl inositol-phospholipase C (PI-PLC) treatment, indicating that this cFc gamma 2a/gamma 3 receptor is a lipid-anchored protein. Preincubation of MAXEY-DH82 with canine sera or canine IgG prevented the binding of murine gamma 2a/gamma 3 Ig, demonstrating that this receptor is a cFc receptor for canine IgG. The cFc gamma R expressed on canine monocytes and on MAXEY-DH82 is probably the analog of the murine and human Fc gamma RI. The specific expression of this analog by canine cells could be used in identifying and purifying canine monocytes.

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PubMedDate not supplied

Anti-alpha chain monoclonal antibodies of equine MHC class-II antigens: applications to equine infectious anaemia.

This paper describes the characteristics of a monoclonal antibody (mAb), 6B11C3, that recognises most equine monocytic cells, as well as B- and T-lymphocytes. The T CD4+ and T CD8+ of this latter population are also stained by the 6B11C3 mAb. On the basis of the distribution of membrane antigens on these cell populations, and of immunohistochemistry results, this mAb appears to be an anti-equine class-II major histocompatibility complex (MHC) antigen. In horses, the hyperexpression of the MHC class-II antigen on T cells is an indication of activated lymphocytes. A decrease in the percentage of lymphocytes stained by 6B11C3 was observed in horses with persistent equine infectious anaemia.

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PubMedDate not supplied

Detection of antibodies to histones in human systemic lupus erythematosus and in murine lupus-like syndromes using micro-ELISA.

An enzyme-linked immunosorbent microassay (micro-ELISA) was improved for the detection of anti-histone antibodies. Detection of these antibodies in autoimmune diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and systemic sclerodermitis sclerosis (SCL), showed a positive correlation between the presence of antinuclear antibodies detected by indirect immunofluorescence and the level of anti-histone antibodies (p less than or equal to 0.02) having anti-H1 (p less than or equal to 0.001) and anti-H2B (p less than or equal to 0.01) specificities. These antibodies were more frequently detected, and at a higher level, in human SLE than in RA and SCL. Anti-H1 and anti-H2B (and less frequently anti-H3) antibodies were also found in mice with lupus-like syndrome (MRL/1, PN and Swan). Their level rose with age and they were prevalent in the severe forms, especially in MRL/1 and PN.

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