Lentivirus vectors (LVs) very efficiently deliver disease antigens when used in vaccines to provoke immune responses. Interestingly, long-term immunity is observed although immunization is accomplished with viral particles that are short-lived and do not replicate. Dendritic cells, antigen-presenting cells, appear to be an important aspect of the long-term immunity seen with the use of these viral particles. After vaccination, there are transduced cells (cells infected with or containing viral particles) at the injection site and lymph nodes well after the lifespan of the dendritic cells of those locations. Therefore, there may be other cells that continue to present LV-encoded antigen to T cells past the dendritic cell life spans.
T-cell receptors (TCRs) are membrane proteins involved in T-cell activation in the presence of an antigen (invading organism or molecule). Each T cell (cytotoxic T cells, T regulatory cells, etc.) has a unique TCR that recognizes a specific antigen. Triggering TCRs result in a number of events in the immune response including the production of cytokines (cell signals), T-cell development, gaining of specific T cells functions, and more.