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Biomedical subjects

E Simpson

Publications and source records attributed to E Simpson.

At least 217 records · Page 12Linked to original sources
PubMed1979

Expression of Ly-6 alloantigen during differentiation of cytotoxic T cells.

We have prepared anti-Ly-6.2 by immunization of (CBA/Ca X A-Thy-1a)F1 with AKR/Crc lymphocytes and used the antiserum to study heterogencity of peripheral T lymphocytes. The Ly-6 alloantigen is found on all activated cytotoxic T cells studied, directed to a variety of different target antigens. The antiserum reveals heterogeneity among the precursors of T killer cells, i.e. allogeneic precursors are Ly-6-, whereas the generation of cytotoxic cells to hapten-modified syngeneic cells and xenogeneic cells is partially abrogated by serum pretreatment. Precursors of some in vivo primed responses are also Ly-6+. These findings indicate that the expression of Ly-6 antigen is, at least, partially related to the stage of T cell activation. The in vitro proliferative response of T cells to allogeneic Ia antigens is substantially reduced by pretreatment with anti-Ly-6.2 serum suggesting that this antiserum may be a useful tool for the study of heterogeneity in the Ly-1+ pool of T cells.

Animals↗
PubMed1979

Use and functional properties of peripheral blood lymphocytes in mice.

Peripheral blood lymphocytes (PBL) were isolated and examined for their ability to respond in vitro to H-2 and H-Y antigens and also to hapten conjugated syngeneic cells. In addition, these lymphocytes were tested as antigen and target cells in in vitro mixed lymphocyte reaction and in chromium release cell mediated lympholysis respectively, as well as serving as targets for the H-2 typing of chimeric mice. Two methods were used to isolate the lymphocytes: a density gradient separation and a double water lysis technique. PBL, prepared by either method compared favourably with splenic lymphocytes in all aspects of anti-H-2 cytotoxicity but could not be used as responder for anti-H-Y cytotoxicity. In addition a method has been developed using PBL as targets for H-2 typing of both allophenic and irradiation chimeric mice. The small numbers of cells required for each of these procedures allows for the preselection of suitable mice and/or multiple experimental determinations on individual mice.

Animals↗
PubMed1978

Cross-reactive cytotoxic responses. H-2 restricted are more specific than anti-H-2 responses.

Cross-reactive T-cell cytotoxicity is seen when cytotoxic responses are generated in mixed lymphocyte cultures either between mouse strans which differ at the major histocompatibility complex, H-2, or between H-2b mutant strains and the strain from which they were derived. This cross-reactivity can be measured with [51Cr] labeled target cells from a number of different H-2 haplotypes, and the pattern of cross-reaction indicates that the target antigens are unlikely to be any of the serologically defined public specificities. In contrast, the specificity of H-2 restricted cytotoxic responses, such as that to the male-specific antigen, H-Y, is exquisite, and male cells from strains of mice carrying H-2 haplotypes other than the responder have never been found to act as appropriate targets. The contrast between the specificity of anti-H-2 and H-2 restricted responses may argue for a greater idiotypic homogeneity of the cells makiing H-2 restricted responses, and the greater specificity of these responses may be necessary for their biological function.

Animals↗
PubMed1978

A survey of weighing performance in clinical biochemistry laboratories.

Results of a survey of accuracy and precision of weighing in a sample of clinical biochemistry laboratories in the U.K. are reported. 101 laboratories each carried out eight weighings. 94% of weighings were subject to errors of not more than 1.7 mg at the 2 g level and not more than 1.0 mg at the 100 mg level. However, 9% of the laboratories produced results which were consistently subject to larger errors.

Chemistry, Clinical↗
PubMed1978

Cytotoxic T-cell responses to H-Y: mapping of the Ir genes.

The secondary cytotoxic responses to the male specific antigen (H-Y) in in mice show H-2 restrictions so that cytotoxic female cells must share K and/or D end antigen with the male target cells. The production of cytotoxic cells is under the control of Ir genes, thus offering the possibility of studying the function of Ir genes in H-2-restricted cytotoxic responses. There are two kinds of Ir genes regulating this response; the dominant gene in the H-2b haplotype and complementary genes in other haplotypes. Now we have been able to map the dominant gene and some of the complementary genes: the dominant genes is in IAb, and in H-2k/H-2d complementation, the Ir genes are in ICk and ICd, and in H-2k/H2s and H-2k/H-2q complementations, at least the H-2k gene is in IC.

Animals↗
PubMed1978

Cytotoxic T-cell responses to H-Y: correlation with the rejection of syngeneic male skin grafts.

The ability of female mice to rapidly reject syngenic male skin grafts is largely determined by dominant genes in the IB region of the H-2b halotype, whereas the ability to produce anti-H-Y cytotoxic cells is determined by a dominant gene in the IA region the H-2b halotype, or by complementary genes in the IC region of some other haplotypes. Thus, it seems that H-2-retricted anti-H-Y cytotoxic T cells are not responsible for the rejection of syngeneic male skin grafts.

Animals↗
PubMed1978

Anti-H-Y responses of H-2b mutant mice.

Two strains of H-2b mutant mice, H-2ba and H-2bf, in which the mutational event took place at H-2K, make anti-H-Y cytotoxic T cell responses which are H-2-restricted, Db-associated and indistinguishable in target cell specificity from those of H-2b mice. Thus, alteration of the H-2K molecule affects neither the Ir gene controlling the response, nor the associative antigen. On the other hand, one H-2Db mutant strain, H-2bo, although it makes a good anti-H-Y cytotoxic response, shows target cell specificity restricted to its own Dbo antigen(s), and neither H-2b, H-2ba or H-2bf anti-H-Y cytotoxic cells kill H-2bo male target cells. Thus, the alteration of the H-2Db molecule does not affect the Ir gene of H-2b mice, but it does alter the H-2Db-associative antigen.

Animals↗
PubMed1978

H-2 complementation in anti-H-Y cytotoxic T-cell responses can occur in chimeric mice.

Cytotoxic T-cell responses against the H-Y antigen in mice are under the control of major histocompatibility complex genes. Not only must cytotoxic T cells recognize both H-Y antigens and "self" H-2K/D molecules to lyse male target cells, but also "appropriate association" between H-Y antigens and H-2K/D antigens is required to induce such cytotoxic responses. Furthermore, it is suggested that appropriate association with H-2-I antigens may also be required to generate H-Y specific helper cells for the cytotoxic response. BALB/c(KdIdDd) mice are nonresponders against syngeneic H-Y antigens, because they lack appropriate associative H-2K/D antigens. This results in the failure of generation of anti H-Y cytotoxic cells, although helper cells may be induced. F1 hybrid mice (BALB/c X C3H/He)F1 or H-2 recombinant mice C3H-OH(KdIdDk) are responders, because H-2Dk (and H-2Kk in the F1) molecules offer appropriate association to H-Y antigens. We here report that allophenic chimeras (H-2d reversible H-2k) and irradiation bone marrow chimeras [H-2d + H-2k leads to F1(H-2d X H-2k)] generate anti-H-Y cytotoxic responses but that cells of the BALB/c(H-2d) genotype comprise most if not all of the cytotoxic cells. A working model is proposed to account for major histocompatibility complex control over anti-H-Y cytotoxic T-cell responses.

Bone Marrow↗
PubMed1978

An evaluation of the Jeol Clinalyzer.

The Jeol Clinalyzer was evaluated over a period of 15 weeks. The operating principles are briefly described. The functions of the mechanical components were tested and assessments made of the instrument's safety and reliability. The mechanical and electrical reliability of the instrument was excellent and the pumps and spectrophotometer gave good accuracy and precision. Between-batch precision of the analytical methods was good for urea, protein and bilirubin and acceptable for alkaline phosphatase and aspartate transaminase. There was a poor relative accuracy for alkaline phosphatase and aspartate transaminase and some proportional inaccuracy for urea and bilirubin.

Alkaline Phosphatase↗