TCR γδ⁺ cells are prominent in normal bovine skin and express a diverse repertoire of antigen receptors

Abstract

SUMMARYMore than 80% of T cells in bovine skin localized in the superficial 0·5 mm of the dermis. Only 3% occurred within the epidermis or made contact with the stratum basale while the remainder occupied deeper dermal sites. The cd T-cell receptor ( TCR) was expressed by 44% of T cells in skin and 39% and 35% expressed, respectively, the CD4 and CD8 markers. Some cells co-expressed CD8 and the cd TCR. A highly diverse repertoire of cd TCR was expressed in skin due mainly to the usage of multiple Vd segments and to extensive sequence variation at the junctions of both TCRc and TCRd chains. However, a single receptor isotype was used. Transcripts encoding several new components of the bovine cd TCR were identified, including three new Vc segments, the Cc5 region and 13 new functional Vd segments. Taken together with earlier findings, these results emphasize that ruminant cd T cells express exceptionally diverse antigen receptors and suggest they may have a more elaborate recognitive capacity than do their counterparts in other species. INTRODUCTIONreflect an ordered programme of gene rearrangement in the thymus, although this possibility has not been examined Several properties of ruminant cd T cells distinguish them directly. A further question that then arises is whether or not from their counterparts in other species. In calves and lambs, specific subsets of ruminant cd T cells with a restricted TCR cd T cells may comprise up to 30-50% of circulating T cells in repertoire either localize or recirculate preferentially to particuthe first few weeks after birth.1,2 Circulating sheep cd T cells lar types of body surfaces. As a first approach to clarifying are derived from a thymus-dependent pathway of diÂeren-this question, we have assessed the frequency and TCR tiation and are almost totally and permanently depleted by diversity of cd T cells in bovine skin, a tissue where these cells removing the thymus about half-way through fetal gestation.3,4 localize prominently.1,11 Our results show that in normal A majority of ruminant cd T cells specifically express a unique bovine skin, cd T cells account for at least 44% of resident accessory molecule, a member of the scavenger receptor family T cells. The cd T cells express an extremely diverse TCR termed WC1, that is encoded by a large and complex family variable-region repertoire but have a restricted usage of one of genes.1,5,6 Finally, ruminant cd T cells express a diverse receptor isotype. repertoire of T-cell receptors ( TCR) encoded by at least five diÂerent Cc segments, around 15-20 diÂerent Vc genes and perhaps as many as 40-50 diÂerent Vd gene segments.7,8 MATERIALS AND METHODS In mice, cd T cells localizing in diÂerent types of mucosal Collection of bovine skin surfaces express a distinctive and usually restricted repertoire Pieces of skin approximately 15×10 cm were collected from of antigen receptors. The populations of cd T cells that colonize the hides of yearling Brown Swiss cattle after slaughter at an diÂerent epithelia arise at distinct stages of fet...

CD3+ and Pax5+ Lymphocytes were not Found in the Dermis of Normal Skin from the Dorsolateral Thorax of Dogs

“…Resident epidermal T-lymphocytes have also been demonstrated in the normal skin of cattle 10) , sheep 9) , and alpacas 6) . Resident dermal T-lymphocytes have been demonstrated in the normal skin of humans 3,8) , cattle 10) , sheep 9) , and in 13 dogs 12,15) .…”

“…Resident dermal T-lymphocytes have been demonstrated in the normal skin of humans 3,8) , cattle 10) , sheep 9) , and in 13 dogs 12,15) . Resident epidermal Blymphocytes have not been demonstrated in humans 3,16) , rodents 18) , dogs 5) , cats 19) , horses 20) , or alpacas 6) .…”

Subset-Specific Regulation of the Lymphatic Exit of Recirculating Lymphocytes In Vivo

“…Furthermore, the use of murine ␥ and ␦ receptor genes is restricted, apparently due to an ordered release from the thymus and similarly ordered colonization of the tissues during development of the immune system (3). Large numbers of ␥␦-T cells can also be found in the skin of ruminants, but there is relatively more variability in receptor gene products (4).…”

γδ+T-Lymphocyte Cytotoxicity against Envelope-Expressing Target Cells Is Unique to the Alymphocytic State of Bovine Leukemia Virus Infection in the Natural Host

“…␥␦ ϩ T lymphocytes in ruminants express a diverse repertoire of the T-cell receptor (TcR) (22,23), and ruminants have an unusually high number of ␥␦ ϩ cells in circulation as well as in certain tissues (9). The possible connection between a ␥␦ ϩ T-cell response and the ability of most BLV-infected animals to avoid severe disease has not been addressed.…”

“…Inherently, the potential for affecting the immune system varies when a different lymphocyte population is the major target for infection. Second, the ␥␦-TcR repertoire in cattle is much greater than in humans (23), allowing for a more diversified ␥␦ ϩ T-cell response in cattle. Here, we test the hypothesis that AL cattle possess lymphocytes capable of lysing cells expressing BLV antigen.…”