Comparative studies of sheep immunoglobulins IgG1 and IgG2: amino acid sequence of carboxy-terminal cyanogen bromide fragments from their heavy chains

Cross-reactivity of monoclonal antibodies to bovine immunoglobulins with immunoglobulins of other species

Monoclonal antibodies (Mabs) to bovine immunoglobulin heavy chain of the four major isotypes gamma 1, gamma 2, alpha, mu and the light chains (combined kappa and lambda) were produced and found to cross-react in enzyme-linked immunoassay (ELISA) with immunoglobulins of some other animal species despite the discrete specificity associated with an antibody derived from a single clone. This cross-reactivity, particularly amongst ruminants, could be utilized in serological testing for the diagnosis of disease in these species. For example, Mabs produced against bovine immunoglobulin light chain cross-react with bison immunoglobulin light chain and were used successfully in serological testing as the secondary detection antibody in an indirect ELISA for the diagnosis of Brucella abortus in bison herds in north-western Canada.

A monoclonal mouse antiallotype antibody reacts with certain human and other vertebrate immunoglobulins: genetic and phylogenetic findings

A new mouse monoclonal antibody, 18.1, recognizes an allotypic determinant on mouse IgG1 of the "a" allotype. We found that this alloantibody reacts with immunoglobulins of evolutionarily distant vertebrate species including man, and with only certain isotypes or allotypes in some of these species. Most mammalian sera are reactive, except those from lagomorphs, marsupials, and monostremes. Avian and reptilian sera are also positive, while the amphibian and fish sera tested were negative. In human sera, 18.1 detects the isotypic marker on IgG2 and an allotypic marker on IgG3. This reactivity parallels the distribution of the Gm non-g determinant. These findings are discussed in relation to the phylogeny of IgG and its subclasses.

Quantitation of immunoglobulins in ovine sera and secretions by laser nephelometry. Comparison with the radial immunodiffusion (RID) technique

In twenty-five ovine body fluids (serum, lung fluid and cerebrospinal fluid), the concentrations of IgG1I, IgG2, IgM and IgA were determined by laser nephelometry and radial immunodiffusion (RID). When nephelometric assays are carried out, antisera free from any turbidity are essential. Methods ensuring that goat and rabbit anti-sera will satisfy this requirement are described in the present paper. When sheep immunoglobulins were measured by laser nephelometry, adequate and reproducible results were obtained, comparable with those obtained by RID. Advantages of the nephelometric method include the speed of assay and its sensitivity, allowing precise determination of the very low concentrations of immunoglobulins in CSF.

Studies on the lymphocytes of sheep. III. Destination of lymph-borne immunoblasts in relation to their tissue of origin

Lymph-borne immunoblasts were labeled in vitro with 125I[]iodo-deoxy-uridine, washed and returned by intravenous injection to the sheep from which they had been collected. Twenty h later the sheep were killed and the distribution of the immunoblasts was determined by assaying the radioactivity in various organs. Immunoblasts from the efferent lymph of peripheral somatic lymph nodes (PSLN) went mainly to the spleen, lungs and other PSLN, while immunoblasts from intestinal lymph went mainly to the small gut. This ability of intestinal immunoblasts to home to the gut was demonstrated also in the sterile environment of fetuses in utero; apparently the migratory behavior of immunoblasts, like that of small lymphocytes, is not primarily "antigen-driven". A technique was devised for the collection of peripheral (i.e. afferent to the mesenteric node) intestinal lymph which was found to contain 10-20 times the numbers of small lymphocytes that occur in the peripheral lymph from other tissues. Immunoblasts from peripheral intestinal lymph also homed to the gut. The immunoglobulin content of immunoblasts was studied by making detergent extracts of lymph cells, by applying immuno-peroxidase techniques to cell films and by investigating the incorporation of 14C-labeled amino acids into immunoglobulins by immunoblasts in vitro. Immunoblasts from both somatic and intestinal lymph contained and made IgG and IgM, but many intestinal immunoblasts contained and made IgA. It is not known whether this immunoglobulin mediates the extravasation of immunoblasts into the gut. Nonetheless, there is compelling evidence that there are two major migratory pathways for lymphoid cells; one through the gut-associated lymphoid tissue and the other through the somatic-splenic lymphoid tissues.

Mouse immunoglobulin subclasses: cyanogen bromide fragments and partial sequence of a gamma1 chain

The purification and characterisation of all the cyanogen bromide fragments of MOPC 21 heavy (gamma1) chain is described. The ten BrCN fragments account for the whole chain. Four of these fragments have been used to establish the sequence of the C-terminal stretch (138 residues) that includes the entire CH3 and a part of the CH2 homology regions. A comparison of this sequence with homologous sequences is presented. Mouse gamma1 and gamma2 proteins differ much more than the gamma subclasses in humans and in other species. The comparison further suggests that the four human gamma subclasses and mouse gamma1 have a common ancestor which differs from the mouse gamma2 ancestor. Unlike other subclasses, mouse gamma1 and gamma2 genes have diverged before speciation.