title: Yes T cells, but three different T cells (alphabeta, gammadelta and NK T cells), and also B-1 cells mediate contact sensitivity.
abstract: Transfer of contact sensitivity (CS) responses by immune lymphoid cells was the first finding that distinguished cellular from humoral immunity. CS has remained the most studied T cell reaction in vivo, and is the prototype for a variety of delayed-type hypersensitivity (DTH) responses. DTH in essence is the recruitment of effector alphabeta-T cells out of vessels into peripheral tissues. The T cells then are activated by antigen presenting cells to produce pro-inflammatory cytokines. It has been assumed that the alphabeta-T cells alone are responsible, but recent studies show that three other lymphocyte subsets are involved: CS-inducing NK T cells, CS-initiating B-1 cells, and CS-assisting gammadelta-T cells. Therefore, the effector alphabeta-T cells are essential, but cannot be recruited into the tissues without the local action of IgM antibodies produced by B-1 cells rapidly (1 day) post-immunization. The IgM complexes with the challenge antigen to locally activate complement to lead to vascular activation required for T cell recruitment. This process occurs early (1-2 hours) in the elicitation phase, and is called CS-initiation. The essential CS-inducing NK T cells activate the B-1 cells by producing IL-4 rapidly (1 hour) after immunization, and gammadelta-T cells assist the local inflammatory function of the recruited CS-effector alphabeta-T cells. Thus, four lymphocyte subsets are required for elicitation of responses: CS-inducing NK T cells, CS-initiating B-1 cells, CS-assisting gammadelta-T cells, and finally the CS-effector alphabeta-T cells. Three of these four cell types are present in the immune lymphoid cell population that adoptively transfers CS: B-1 cells, gammadelta-T cells, and the alphabeta-T cells.
authors.affiliation: Section of Allergy and Clinical Immunology, Yale University School of Medicine, New Haven, CT 06510, USA. philip.askenase@yale.edu
authors.forename: P W
authors.initials: PW
authors.lastname: Askenase
mesh_terms: D001402:B-Lymphocytes; D003877:Dermatitis, Contact / Q000209:etiology*; D006801:Humans; D007111:Immunity, Cellular; D007075:Immunoglobulin M / Q000096:biosynthesis; D007694:Killer Cells, Natural / Q000276:immunology*; D018448:Models, Immunological; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D007075:Immunoglobulin M; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta