Immunization of HLA-B27 transgenic and non transgenic mice with Salmonella typhimurium results predominantly in the generation of proliferative T cell responses

Optimization of the delivery of heterologous proteins by the Salmonella enterica serovar Typhimurium type III secretion system for vaccine development

Type III protein secretion systems, which are organelles with the capacity to deliver bacterial proteins into host cells, have been adapted to deliver heterologous antigens for vaccine development. A limitation of these antigen delivery systems is that some proteins are not amenable to secretion through this pathway. We show here that proteins from the simian and human immunodeficiency viruses that are not permissive for secretion through a Salmonella enterica serovar Typhimurium type III secretion system can be modified to travel this secretion pathway by introduction of discrete mutations. Proteins optimized for secretion were presented more efficiently via the major histocompatibility complex class I pathway and were able to induce a better immune response.

Reactive arthritis: the result of an anti-idiotypic immune response to a bacterial lipopolysaccharide antigen where the idiotype has the immunological appearance of a synovial antigen

The term reactive arthritis (ReA) was first used in 1969 to describe sterile joint disease that follows infection elsewhere in the body. This is an attempt to explain the immunological basis of this disease, give a rationale for the presence of a single bacterial antigen in the involved joints, explain why the class I MHC molecule HLA-B27 is necessary and to suggest possible therapy. This paper proposes an anti-idiotypic (anti-id) model for this disease where a bacterial lipopolysaccharide (LPS) epitope is recognized by idiotypic (Id) T cell receptors and antibody Fab immune recognition surfaces (IRS) which have the immunologic appearance of an antigen on the synovial surface. These Id immune effectors utilize an HLA-B27 molecule to present their IRS on their surface, which results in an anti-id response that can also target the synovial antigen. The anti-id IRS have the immunologic appearance of LPS and their detection in the arthritic joint falsely suggests the presence of bacterial LPS. Evidence is presented which supports this reactive arthritis model in which there is a synovial antigen that is attacked by an anti-id response against the LPS of arthritogenic bacteria. Therapeutic vaccination is supported by this hypothesis.

The use of human leucocyte antigen class I transgenic mice to investigate human immune function

HLA class I transgenic mice are a powerful research tool which have been used as models for human immune responses. This review describes the generation of the different HLA class I transgenic mice, the techniques used to improve expression of the transgene and use of the transgene product in immune responses. It also illustrates how HLA class I transgenic mice have provided insights into the nature of the allogeneic and xenogeneic response, the generation of CTL responses, the development of autoimmune diseases, and their use for the generation of anti-HLA class I antibodies. Despite these advances, the use of available HLA class I transgenic mice as models for human disease and immune responses has been limited. The development of new transgenic strains incorporating multiple human transgenes may allow the potential of HLA class I transgenic mice to be realised.

Delivery of epitopes by the Salmonella type III secretion system for vaccine development

Avirulent strains of Salmonella typhimurium are being considered as antigen delivery vectors. During its intracellular stage in the host, S. typhimurium resides within a membrane-bound compartment and is not an efficient inducer of class I-restricted immune responses. Viral epitopes were successfully delivered to the host-cell cytosol by using the type III protein secretion system of S. typhimurium. This resulted in class I-restricted immune responses that protected vaccinated animals against lethal infection. This approach may allow the efficient use of S. typhimurium as an antigen delivery system to control infections by pathogens that require this type of immune response for protection.