Immunohistochemical localization of galactosyltransferase in human fibroblasts and HeLa cells.

Anti-human galactosyltransferase (E.C. 2.

Resistance and susceptibility of mice to bacterial infection: histopathology of listeriosis in resistant and susceptible strains.

C57BL/10 mice have previously been shown to be 100 times more resistant to intravenously injected Listeria monocytogenes than are BALB/c mice due to the action of a single gene, Lr. Differences in the histopathology of listeriosis in the two strains were sought. Of the tissues examined, only liver, spleen, blood, and thymus showed changes.

Use of spleen organ cultures to monitor hemopoietic progenitor cell regeneration following irradiation and marrow transplantation.

After lethal irradiation of C57BL mice followed by the injection of 10(7) marrow cells, total cellularity and progenitor cell levels exceeded pretreatment levels within 12 days in the spleen, but regeneration remained incomplete in the marrow. The exceptional regenerative capacity of progenitor populations in the spleen was observed in organ cultures of spleen slices prepared 24 hr after irradiation and transplantation, excluding continuous repopulation from the marrow as a significant factor in splenic regeneration.

Analysis of rat hemopoietic cells on the fluorescence-activated cell sorter. II. Isolation of terminal deoxynucleotidyl transferase-positive cells.

A method is described by which highly enriched populations of viable terminal deoxynucleotidyl transferase-positive (TdT+) cells can be isolated from rat bone marrow by use of the fluorescence-activated cell sorter. Such cells have been postulated to be progenitors of thymocytes and, possibly, of B lymphocytes, and may serve as the targets of neoplastic transformation in acute lymphoblastic leukemia. The separation procedure is based on differences in relative low-angle light scatter and relative fluorescence intensity for Thy-1 antigen between TdT+ cells and other lymphohemopoietic cell populations in bone marrow.

Analysis of rat hemopoietic cells on the fluorescence-activated cell sorter. I. Isolation of pluripotent hemopoietic stem cells and granulocyte-macrophage progenitor cells.

A scheme is presented whereby pluripotent hemopoietic stem cells (PHSC) from rat bone marrow can be enriched 320-fold with the aid of the fluorescence- activated cell sorter. This scheme is based on the observations that PHSC are strongly positive for Thy-1 antigen (upper 10th percentile); have light- scattering properties (size distribution) between those of bone marrow lymphocytes and myeloid progenitor cells; and are relatively resistant to cortisone. It is estimated that PHSC may constitute 80 percent of the cells isolated according to these parameters.

Antibody isotypes mediating antigen retention in passively immunized mice.

Antibody isotypes vary in their capacity to mediate retention of a readily catabolized protein antigen, human serum albumin (HSA) in spleen, popliteal lymph node (PLN) and hind foot. Hyperimmune anti-HSA mouse sera were separated into fractions highly enriched for IgM, IgG1 and IgG2 via differential elution from protein A-Sepharose. These fractions were used to immunize normal mice passively.

Immune elimination and immune retention: the relationship between antigen retained in the foot and the elicitation of footpad swelling.

We determined whether (1) long term antigen retention is present in distal sites after footpad challenge of immune mice; (2) if antigen retained in the foot is selectively localized; and (3) if the foot is adversely affected by the retained antigen. Mice immune or non-immune to human serum albumin (HSA) were injected in the hind footpads with 125I-HSA. In immune mice rapid clearance of radiolabel occurred in the liver, lungs, kidney, blood and urine but radiolabel was retained in the hind feet, draining lymph nodes and spleen.

The presence of mast cells in agar cultures.

Using a specific stain and electron microscopy, small numbers of mast cells were detected in human bone marrow cultures. However, they were not detected in agar cultures containing murine bone marrow cells. In bone marrow cultures from three patients with acute myeloid leukemia the number of mast cells was elevated.

Ontogenic development of B-lymphocyte function and tolerance susceptibility in vivo and in an in vitro organ culture system.

The maturation of B-lymphocyte function during fetal development was studied in vivo and in an in vitro organ culture system. The results indicated that the progenitors for 2,4-dinitrophenol (DNP)-specific B cells are present as early as 14 d of gestation in liver and possibly as early as 15 d in spleen. In addition, it was found that the organ culture system supports the development of B lymphocytes as measured by an increase in both the percentage of surface immunoglobulin-positive cells and the frequency of clonable DNP-specific B cells after culturing.

Immune retention: immunological requirements for maintaining an easily degradable antigen in vivo.

Radioactive human serum albumin (125I-HSA) was injected into the hind foot pads of unimmunized mice, actively immunized mice and mice passively immunized with mouse or rabbit anti-HSA serum. Eleven days later the unimmunized mice had cleared most of the 125I-HSA. In contrast, a high concentration of 125I-HSA was retained in the feet and draining lymph nodes and, to a lesser extent, in the spleen of the actively or passively immunized mice.

Surface immunoglobulin on cultured foetal mouse thymocytes.

Organ cultures of 14–15 day foetal mouse thymus were used as a source of non-neoplastic differentiating T cells, free of contaminating B cells. Viable cells obtained from such cultured thymuses were radio-iodinated and immunoglobulins (Ig) were isolated by co-precipitation from the I-labelled cell-surface proteins released during 1 h of incubation at 37°. The precipitates, both reduced and unreduced, were then analysed by polyacrylamide gel electrophoresis.

Prolonged antigen half-life in the lymphoid follicles of specifically immunized mice.

The kinetics of clearance of I from the popliteal lymph nodes and feet of human serum albumin (HSA)-immunized mice was studied following the injection of [I]-HSA into the hind footpads. Antigen was cleared from both locations rapidly for the first few days. The antigen half-life (½) during this period was only a matter of hours.

Colony formation in agar by multipotential hemopoietic cells.

Agar cultures of CBA fetal liver, peripheral blood, yolk sac and adult marrow cells were stimulated by pokeweed mitogen-stimulated spleen conditioned medium. Two to ten percent of the colonies developing were mixed colonies, documented by light or electron microscopy to contain erythroid, neutrophil, macrophage, eosinophil and megakaryocytic cells. No lymphoid cells were detected.