A block in both early T lymphocyte and natural killer cell development in transgenic mice with high-copy numbers of the human CD3E gene.

Abstract

A severe immunodeficiency involving a complete loss of T lymphocytes and natural killer cells was observed in independent lines of transgenic mice containing >30 copies of the human CD3E gene (pL12). T-cell natural killer (NK)-mice could also be generated by using a gene fragment pL12A1 (without exons 4A and 5) coding for the CD3-e transmembrane region and its 55-amino acid nonenzymatic cytoplasmic tail. The abnormally small thymus gland in the homozygous transgenic animals, which was 41% the size of a wild-type thymus, contained only a few (2-4%) prethymocytes with a Thy-l+Pgp-1+IL-2Ra-CD3-4-8-phenotype. In mice with lower copy numbers of the transgene thymocyte development was blocked at the Thy-l+Pgp-1lIL-2Ra+CD3-4-8-stage, and normal NK activity was detected. Mice generated with high-copy numbers of a transgene pL12A2 (pL12A1 minus exons 6), coding for a truncated protein from which the CD3-E extracellular domain, its transmembrane region, and most of its cytoplasmic region were absent, contained normal numbers of T lymphocytes and NK cells. These transgene effects suggested that recruitment of signal-transduction molecules by the cytoplasmic tail of this protein played an important role in the abrogation of both lineages. Taken together these observations support the notion that T lymphocytes and NK cells stemmed from a common precursor.Antigen CD3-e plays a dual role in the six-polypeptide-chain T-cell antigen receptor: initiator of receptor assembly within the endoplasmic reticulum and transducer of the signal generated by antigen recognition (1-3). More recently it has become clear that incomplete CD3 complexes, which are T-cell receptor (TCR)-ac, -(-, -y-, and -8-, can be detected on the surface of CD4-8-thymocytes. These extremely low levels of cell-surface CD3-y, -8, and -E are potentially functionally competent because antibodies directed at CD3-e trigger one of its signal-transduction pathways and drive differentiation from CD4-8-to CD4+8+ thymocytes in the absence of TCR gene rearrangements (4). Intracellular CD3-E protein was found in human natural killer (NK) cells (5) and more recently, studies using cultured human fetal thymus and fetal liver clones revealed that CD3-E could also be found in NK cell precursors (6, 7

The Cryptococcal Enzyme Inositol Phosphosphingolipid-Phospholipase C Confers Resistance to the Antifungal Effects of Macrophages and Promotes Fungal Dissemination to the Central Nervous System

“…Next, we investigated whether this virulence phenotype of the ⌬isc1 mutant would also be present in an immunodeficient animal model. For this experiment, we used the isogenic Tgε26, deficient in T and NK cells (47,48). In this model, the average survival of the WT-infected mice was 15.7 Ϯ 1.0 days and the average survival of the ⌬isc1 strain-infected mice was 19.4 Ϯ 2.0 days, and interestingly, there was no significant difference in fungal burden in brain tissue between WT-and ⌬isc1 strain-infected mice (data not shown), suggesting that the ⌬isc1 strain does infect and replicate in the brain tissue at the same rate of WT cells when the host immune system is severely compromised.…”

“…Four-to sixweek-old female CBA/J mice (Jackson Laboratory, Bar Harbor, Maine) and four-to six-week-old male/female Tgε26 mice (an isogenic mouse line lacking in mature T cells and NK cells [47,48], available in the Animal Core Facility, Medical University of South Carolina, Charleston, SC) were used. Mice were anesthetized with an intraperitoneal injection of 60 l of xylazine/ketamine mixture, containing 95 mg of ketamine per kilogram of body weight and 5 mg of xylazine per kilogram of body weight.…”

Dissociation of Hemopoietic Chimerism and Allograft Tolerance After Allogeneic Bone Marrow Transplantation

“…Five of seven mice promptly rejected wtB6129SF 2 skin allografts even in the presence of a high-degree donor chimerism (Table I, group e, and Table III, group f). The dissociation of hemopoietic chimerism and allograft tolerance was also observed with the use of BMC from CD3E-tg mice, which are deficient in all T cells and NK cells (13) (Table I, group f, and Table III, group h). On day 28 after BMT, the degree of chimerism was moderate, with approximately one-half of B10.D2 (H-2 d ) recipients showing Ͻ50% chimerism.…”

“…B10.A (H-2 a ) mice (Charles River Laboratories, Kingston, NY) and B10.D2 (H-2 d ) mice (The Jackson Laboratory, Bar Harbor, ME) were used as BMT recipients. BMC donors included wild-type (wt) C57BL/6 (wtB6; H-2 b ) mice (Taconic Farms, Germantown, NY), B6 mice deficient in CD4 expression (CD4 knockout (KO)) (10) or CD8a expression (CD8 KO) (11), B6129SF 2 (H-2 b/b ) mice deficient for both CD4 and CD8a expression (CD4/8 double KO (DKO) mice) (12), and B6CBAF 1 (H-2 b/k ) mice carrying a human CD3E transgene (CD3E-tg mice) (13). T cell-deficient mice, their wt controls, and DBA/1 mice were purchased from The Jackson Laboratory.…”

Identification of the primary outcomes that result from deficient spiral arterial modification in pregnant mice

“…BALB/c +/+ weights at weeks [10][11][12][13][14][15][16], that were statistically less than agematched weights of Rag2 −/− /Il2rg −/− , are measurements on animals in our care. At 10 weeks of age, female Rag2 −/− /Il2rg −/− mice were on average 3.2 g heavier that BALB/c mice (P<0.001), a finding that had implications for our anaesthetic protocol and overall postsurgical success for surgical implantation of radiotransmitters in BALB/c control mice (see below).…”