Insertional mutation of the hairless locus on mouse Chromosome 14

Crosses between heterozygous transgenic mice from line 5053 produced offspring with progressive irreversible hair loss beginning at day 10. With increasing age, the skin of these animals became thicker and plicated in appearance. Histological analysis revealed the complete absence of normal hair follicles and numerous intradermic cystic structures, which enlarged with time and became filled with keratinaceous material. Test crosses demonstrated that the affected animals are homozygous for the transgene insertion. The clinicla and histological phenotype of the new mutant closely resembles that of the rhino allele at the hairless locus on Chromosome (Chr) 14. Complementation tests and linkage analysis indicate that the transgene has interrupted the hairless locus. It has been demonstrated previously that mutation at the hr locus is accompanied by a variety of immune deficiencies. Many of the older affected transgenic mice developed an impetigo-like skin eruption which responded to antibiotic ointment and which may reflect impaired immune function. The transgenic allele, hr TgN5053Mm , will be useful for identification of the transcription unit of the hairless locus.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47000/1/335_2004_Article_BF00360900.pd

Antigen- and receptor-driven regulatory mechanisms. X. The induction and suppression of hapten-specific granulomas.

We have investigated the induction and suppression of granuloma formation elicited by the azobenzenearsonate (ABA) determinant in A/J Mice. ABA-derived syngeneic spleen cells (ABA-SC) administered subcutaneously induced hapten-specific delayed hypersensitivity (DTH), detected by footpad swelling, upon challenge with ABA-bovine serum albumin (BSA) coupled to polyacrylamide beads (PAB). The reactions elicited by ABA-BSA-PAB reached maximal intensity at 24 hours but were relatively persistent and were still marked at 96 hours. Histopathologic examination of footpad responses at 24 and 48 hours after challenge revealed compact collections around beads of mononuclear cells and granulocytes, which were characteristic of DTH reactions. Discrete epithelioid granulomas became apparent by 72 or 96 hours. Unprimed mice or mice primed with ABA-SC and challenged with uncoupled beads did not develop either substantial leukocytic infiltrates or granulomas. Persistent delayed responses were only apparent if the mice were challenged with the homologous hapten-coupled bead, indicating the fine specificity of the reaction. Immune cells were shown to be capable of transferring DTH and granulomatous responsiveness to ABA; the cells were sensitive to anti-Thy 1.2 antiserum and complement, which indicates that the response was thymic-dependent. The intravenous injection of ABA-SC, which is known to induce suppressor cells, prevented the development of DTH or granulomatous responsiveness followinggg subcutaneous immunization with ABA-SC. In addition, the transfer of suspensions containing suppressor T cells into syngeneic mice primed with ABA-SC prevented the development of DTH reactions and granuloma formation followin challenge with ABA-BSA-PAB. Furthermore, only hapten-specific suppressor T cells limited persistent delayed hypersensitivity responses. Having successfully developed granulomas in the footpad, the authors induced and suppressed granulomatous lesions in the gastrointestinal tract in a similar fashion. These experiments establish a model in inbred mice for the study of granulomatous diseases, including those of the gastrointestinal tract