Cattle immune responses to tetanus toxoid elicited by recombinant S. typhimurium vaccines or tetanus toxoid in alum or Freund's adjuvant.

Cattle were immunised orally, nasally or subcutaneously with either S. typhimurium 4/74 aroA(-) aroD(-) or S. typhimurium 4/74 htrA-based live vaccines expressing Fragment C (TetC) of tetanus toxin from plasmid pTetnir15. Oral inoculation with S. typhimurium 4/74 aroA(-) aroD(-)- (pTetnir15) elicited mucosal anti-TetC IgA but no measurable systemic humoral responses to TetC. Subcutaneous inoculation with the same strain elicited both mucosal IgA and systemic anti-TetC IgG1 responses. Nasal inoculation did not elicit any detectable anti-TetC responses. Oral delivery of S. typhimurium htrA(-) proved fatal in inoculated animals. None of the animals inoculated with either mutant S. typhimurium developed detectable T cell proliferative responses to the guest antigen. Cattle were also inoculated with tetanus toxoid adsorbed in alum or emulsified in Freund's complete adjuvant. Animals inoculated subcutaneously with Ttox emulsified in FCA developed systemic IgG1 and IgG2 antibody, while animals inoculated with Ttox adsorbed in alum developed systemic IgG1 but little IgG2 to Ttox. Both of these groups of animals developed measurable TetC-specific proliferative T cell responses that were associated with the production of IFNgamma.

Selection of specific phage-display antibodies using libraries derived from chicken immunoglobulin genes.

In chickens, single functional immunoglobulin variable and joining gene segments at each of the heavy and light chain loci undergo V(D)J rearrangement. Diversity is subsequently introduced by conversions templated by upstream pseudo V region genes in such a way that practically all V regions in mature B cells have identical ends. This greatly simplifies the representative amplification of V region genes. Furthermore, the entire naive repertoire of the adult chicken is produced in the bursa of Fabricius of the young bird. These special properties of the generation of immunoglobulin diversity in chickens have been exploited in the development of procedures to produce large libraries of diverse antibody combining sites derived from chicken Ig genes and expressed on filamentous bacteriophage. The utility of this library was assessed by selection of specifically binding phage using three solid phase-bound protein antigens, hen egg white lysozyme, bovine thyroglobulin and bovine serum albumin. The sequences of the V region genes thus isolated demonstrated that selection was specific and that the library contained useful diversity of binding sites. This library provides access to a repertoire whose diversity is based on a mechanism different from that underlying previously available libraries. The demonstrated feasibility of generating chicken phage antibodies may lead to the production of monoclonal reagents from immunised chickens, and the derivation of reagents for studying immunoglobulin mediated selection in avian B cell development.

Expression on porcine gamma delta lymphocytes of a phylogenetically conserved surface antigen previously restricted in expression to ruminant gamma delta T lymphocytes.

A 180,000 MW molecule has been identified on porcine leucocytes that is the homologue of the 215,000/300,000 MW WC1 (T19) leucocyte antigen previously considered to be restricted to ruminants. In ruminants the WC1 molecule is expressed by a T-cell subpopulation that is CD2-CD4-CD8-CD5+ and that is gamma delta T-cell receptor positive (TcR+). In pigs, the 180,000 MW molecule, identified by a new monoclonal antibody CC101, is expressed by a gamma delta TcR+ T-cell subpopulation that is also CD2-CD4-CD8-. The p180+ cells are a major T-cell subpopulation comprising approximately 40% of the peripheral blood mononuclear cells from 6-9-month-old pigs. Expression of p180 identifies the majority of the CD2-CD4-CD8- T cells in porcine blood. The p180+ T cells have a distribution in lymphoid tissues that is distinct from that of T cells that express the CD2, CD4 or CD8 molecules. They are evident particularly in the thymic medulla, the epithelium, lamina propria and interfollicular areas of the small intestine, and the superficial dermis of the skin, but largely absent from conventional T-dependent areas of secondary lymphoid tissue.