Prominence of γδ T Cells in the Elicitation Phase of Dinitrochlorobenzene-induced Contact Hypersensitivity in Lambs

Abstract

Immunohistochemical techniques were used to identify T-cell subpopulations in the ear skin of lambs during the elicitation phase of dinitrochlorobenzene (DCNB)-induced contact hypersensitivity. Thirty lambs (21-26 weeks of age) were divided into groups of 10. The shaved right ear of one group was treated with DNCB. Two weeks later, this group was challenged with DNCB. One group was treated with the vehicle alone, and the remaining group was left untreated. The lambs were killed 48 hours after challenge, and tissue specimens were collected from the ears of the three groups. There was an increase in T-cell populations in the skin of the DNCB-treated lambs 48 hours after challenge. The majority of the T cells were CD8+ and associated predominantly with the blood vessels and adnexa of the superficial dermis. There was also an increased presence of CD4+ cells and gammadelta T cells in the superficial dermis. In the epidermis, clusters of gammadelta T cells and CD4+ cells were associated with microlesions. Computer-assisted morphometric analysis was used to estimate the relative presence of the T-cell subpopulations in the superficial and deep dermis and the entire dermis. Statistical analysis of the relative area of immunostaining showed that the significant increases in all T-cell subpopulations (CD4+, CD8+, and gammadelta T cells) in the entire dermis were accounted for by changes in the superficial dermis. The prominence of gammadelta T cells in delayed-type hypersensitivity in the skin of domestic ruminants has been the subject of conflicting reports. In the present study, CD4+ cell and gammadelta T-cell populations were of similar size in the normal and DNCB-treated lambs, suggesting an equal participation in the elicitation phase of contact hypersensitivity.

Yes T cells, but three different T cells (αβ,γδand NK T cells), and also B-1 cells mediate contact sensitivity

“…We postulate that the CS‐assisting γδ T cells are also recruited by CS‐initiating mechanisms to optimize the effector αβ ‐T cell responses. Indeed, it has been shown that γδ ‐T cells are a major component of the cellular infiltrate in CS responses of lambs, that like other ruminants have large numbers of circulating and lymphoid γδ ‐T cells [21].…”

“…Then in the extravascular tissues, while the CS‐effector αβ ‐T cells are interacting via cognate specificity with hapten‐peptide‐MHC complexes on APC, the γδ ‐TCR of CS‐assisting cells interact via their γδ ‐TCR with either native activation proteins, or with low molecular weight phenyl pyrophosphate or alkamine‐like ligands, expressed via the activated αβ ‐T cells, or APC or keratinocytes, etc., to then assist the αβ ‐T cells. The surface expressed antigens that activate the γδ ‐TCR could be heat shock proteins or minor histocompatability antigens that become newly expressed via nonspecific skin cell activation via NF‐ κ B pathways that are stimulated by the irritating nonspecific contact hapten challenge [21]. Binding of γδ ‐TCR to these surface complexes may then activate the γδ ‐T cells to positively influence the recruited CS‐effector αβ ‐T cells, thereby optimizing their production of Th1 cytokines to subsequently generate full elicitation of CS inflammation.…”

Morphologic and Immunohistochemical Features of Experimentally Induced Allergic Contact Dermatitis in Göttingen Minipigs

“…The changes seen in DNFB-ACD sites 8 hours after elicitation of the hypersensitivity reaction consisted of a mild hyperplastic epidermis with spongiosis and inflammatory cells in the lower layers. In the uppermost portion of the dermis, vasodilatation, perivascular edema, and cellular infiltration were present, overall scored at 17.0 (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29). Subsequently, these changes increased and reached maximal intensity 24-48 hours after challenge (scores 31.5 and 33.0 [27][28][29][30][31][32][33][34][35][36], respectively).…”

γδ T‐cell lymphoma in a cow

“…Similar portions of the epidermis have been found to be infiltrated with clusters of γδ T cells in lambs experimentally sensitised with dinitrochlorobenzene. 9 Numerous intraepithelial WC1 + cells were evident in the bovine small intestine in one earlier study, 10 but, in another, WC1 + cells were a minor population of bovine intestinal…”