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H A Ward

Publications and source records attributed to H A Ward.

9 recordsLinked to original sources
PubMed1979

Detection of early lymphocyte activation by the fluorescent cell membrane probe N-phenyl-1-naphthylamine.

N-phenyl-1-naphthylamine (NPN) becomes fluorescent after binding to hydrophobic regions of cell membranes. Rat and mouse lymphoid cell suspensions stained with NPN showed changes in fluorescence emission 30 min after stimulation with mitogen or antigen, detected by microfluorimetry. Incubation of NPN-labelled mouse and rat thymocytes with phytohaemagglutinin or concanavalin A (Con A) caused an increase in mean cell fluorescence intensity. The response to Con A was inhibited by sodium azide and alpha-methyl mannoside. Stimulation of spleen cells from mice by allogeneic cells, or from tumour-bearing rats by tumour antigen consistently resulted in decreased fluorescence. The 'mixed lymphocyte response' detected only certain genetic differences between mouse strains and was proportional to the ratio of stimulator to responder cell number. The NPN staining procedure offers a simple and rapid assay of immunoreactivity and a means of studying early subcellular changes following lymphocyte activation.

1-Naphthylamine↗
PubMed1979

Immunoassays.

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Enzyme-Linked Immunosorbent Assay↗
PubMed1979

Rhodamine as a fluorescent probe of lymphocyte activation.

Fresh rat and mouse lymphoid cells have been labelled by stable linkage with tetramethylrhodamine isothiocyanate (TMRITC). A change in intensity, either an increase or decrease of the fluorescent emission of the cells, detected by microfluorimetry, was induced by mitogen stimulation or the mixed lymphocyte reaction. The change in fluorescence was observed within 3 h of mitogen stimulation and within 0.5 h in the mixed lymphocyte test. These early cellular responses were detectable consistently whether the labelling was done before or after mitogen stimulation; post-labelling only was studied in the mixed lymphocyte reaction. The method should provide a time-saving practical procedure for early detection of the lymphoid cell responses and would readily lend itself to flow cytofluorimetry for possible routine diagnostic use.

Animals↗
PubMed1978

Lymphoid antigenic determinants of the chicken. Cellular representation and tissue localization.

Antisera were prepared against a variety of chicken tissues with a view to detecting antigens specific for subpopulations of T and B cells at different maturation stages. By appropriate absorption analysis, the following antigens were defined: (a) thymus organ-specific antigen (CTOA); (b) T lymphocyte-specific antigen (CTLA); (c) B lymphocyte-specific antigen (CBLA); (d) mature B lymphocyte-specific antigen (CMBLA); (e) a foetal-associated antigen (CFAA) present on embryonic haemopoietic cells, and adult bone marrow and immature bursa cells, suggesting the cell types concerned may be at an early stage of development, possibly including precursors. For comparison with the above antigens, cells were also examined for surface Ig and IgG. T cells were found in periarteriolar sheaths in the spleen, and predominantly in the sub-epithelium and sub-mucosa of the caecal tonsil of the gut-associated lymphoid tissue (GALT). B cells were localized in periellipsoidal sheaths and germinal centres in the spleen, and in primary follicles or germinal centres in the GALT. The thymic and bursal medullas contained the mature populations of T and B lymphocytes respectively.

Animals↗
PubMed1976

Antiserum specific for reticulin of the bursa of fabricius.

Antiserum produced by immunizing rabbits with embryonic chicken spleen cells showed, after appropriate absorption with cell suspensions, specificity for fetal spleen cells in membrane immunofluorescence tests. However, when the original antiserum was absorbed with tissue homogenates and tested on cryostat tissue sections, it reacted specifically with the reticular framework which separates the cortical and medullary lymphocytes in the follicles of the adult bursa of Fabricius. It is suggested that the reticulin may influence bursal lymphoid differentiation.

Animals↗