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Biomedical subjects

H D Kay

Publications and source records attributed to H D Kay.

At least 37 records · Page 2Linked to original sources
PubMed1982

Vaccination of the African white-tailed rat, Mystromys albacaudatus, with sonicated Leishmania braziliensis panamensis promastigotes.

The usefulness of sonicated Leishmania braziliensis panamensis promastigotes for vaccination was evaluated in Mystromys albacaudatus, the African white-tailed rat. Thirty-two animals received three intradermal injections of 2 x 10(6) sonicated promastigotes derived from L. braziliensis panamensis at weekly intervals. One month after completion of the immunization schedule, the experimental group of animals was challenged in vivo with 2 x 10(6) live L. braziliensis panamensis promastogotes. At the same time, a matched group of 40 control animals was similarly challenged. Within 2 months, 35 of the 40 animals (87.5%) the control group developed ulcers, while only 14 of 32 previously vaccinated animals (43.7%) developed ulcers at the site of challenge within the same time period. The remaining 18 vaccinated animals (56.2%) remain free from ulcers 7 months after challenge. When lymphocytes from the spleens of vaccinated and control animals were challenged in vitro with antigen derived from sonicates of varying numbers of promastigotes, only cells from immunized animals responded vigorously to the antigenic challenge, a response which was not enhanced by the addition of immune antiserum to the reaction.

Animals↗
PubMed1980

A new procedure to overlay diluted blood on Ficoll-hypaque gradients.

A simple procedure is described which permits rapid layering of large volumes of diluted blood onto Ficoll-Hypaque gradients with no requirement for specialized syringes, cannulas, pipettes, or support racks. In use for several years, the method is as good as, or better than, other techniques.

Blood Cells↗
PubMed1980

Evidence by reactivity with hybridoma antibodies for a probable myeloid origin of peripheral blood cells active in natural cytotoxicity and antibody-dependent cell-mediated cytotoxicity.

Lymphocytes with Fc receptors (FcR) for IgG active in natural cytotoxicity and antibody-dependent cellular cytotoxicity were separated into sheep erythrocyte rosetting (E+) and nonrosetting (E-) fractions, and examined for reactivity with the OK panel of hybridoma-produced monoclonal antibodies. Few cells in either the E+ FcR+ or the E- FcR+ fraction reacted with seven antibodies used to define T cells in various stages of differentiation (OK3, OKT4, OKT5, OKT6, OKT8, OKT9, OKT10). Neither fraction expressed an Ia-like antigen (detected by OKI1), but both were highly reactive with OKM1, an antibody that reacts with monocytes and granulocytes. Incubation of these cytotoxic effector cells with OKM1 plus complement abolished all cytotoxic reactivity, but incubation with a pan-T cell antibody (OKT3) plus complement had no significant effect. These cells were not monocyte precursors, because they could not be induced in vitro to develop macrophage characteristics. The data indicate that most cytotoxic effector cells in natural cytotoxicity and antibody-dependent cellular cytotoxicity are not in the T cell lineage, but have a myeloid origin.

Antibodies↗
PubMed1979

Cytotoxicity against the K562 erythroleukemia cell line by human natural killer (NK) cells which do not bear free Fc receptors for IgG.

When Fc receptors (FcR) on normal human peripheral blood lymphocytes were induced to modulate by overnight (18 h) incubation in the presence of soluble or particulate immune complexes, the natural killer (NK) activity of the effector lymphocyte suspension, as measured against the K562 erythroleukemia cell line, was significantly, but only partially, inhibited. The NK activity which remained was always strong, and was not significantly inhibited by inclusion of antigen-antibody complexes in the cytotoxicity assay, nor was it further depleted by adsorbing the modulated cells on plastic surfaces coated with immobilized antigen-antibody complexes. Antibody-dependent cell-mediated cytotoxicity (ADCC) against rabbit antibody-sensitized Chang liver cells was totally abrogated following the modulation process, and could not be restored by exposure of modulated effector cells to trypsin, indicating that the FcR had actually been shed and were not merely being blocked with immune complexes. Although freshly isolated peripheral blood lymphocytes active in natural (or "spontaneous") cytotoxicity have been shown to bear FcR, our data indicate that NK activity against the K562 cell line can be effectively mediated by NK cells which have lost their FcR. This supports the concept that NK activity against K562 is independent of FcR, and, therefore, of IgG.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1977

Natural cytotoxic reactivity of human lymphocytes against a myeloid cell line: characterization of effector cells.

Using a series of techniques to identify and deplete various peripheral blood lymphocyte subpopulations, we studied the cytotoxic reactivity of normal individuals against the myeloid cell line K-562 in a 4-hr 51chromium-release assay. Depletion of lymphocytes bearing complement receptors had a variable, usually negligible effect on cytotoxicity. In contrast, depletion of lymphocytes bearing Fc receptors abrogated target cell lysis. Separation of lymphocytes with high-affinity binding of sheep red blood cells (SRBC) evidenced by rosette formation at 29 degrees C yielded a population of rosette-forming cells containing few cytotoxic cells, whereas separation of total E-RFC under optimal rosetting conditions produced a rosette fraction containing a major proportion of the effector cells. These data indicate that the cytotoxic lymphocyte in this system is Fc receptor positive, largely complement receptor negative, and may possess low density or low affinity receptors for SRBC.

Antigen-Antibody Complex↗
PubMed1975

Growth of permanent lymphoid cell cultures from human source: tenth anniversary.

The authors developed 52 permanent lymphoid cell cultures from various human sources, mainly from neoplastic lymphoproliferative disease. These cultures are reviewed against the background of similar cultures obtained in several other laboratories. The peculiar features of these cultures are: 1) the phenomenon of lymphoblastoid transformation; 2) the production of both globulins and mediators of delayed hypersensitivity; 3) the presence of herpes type virus as related to etiology or autoimmunity; and 4) cytotoxicity and other assays for the demonstration of tumor-specific antigens.

Animals↗