T. Makinodan

Circulating rat cells in lethally irradiated mice protected with rat bone marrow.

Summary 1. Mice receiving 950 r can be protected from the 30-day irradiation death by injecting rat bone marrow and caging them individually. 2. Transplantation of rat erythrocytopoietic and granulocytopoietic cells has been demonstrated by the appearance of rat RBC and granulocytes in the circulation. On the 65th day, 100% rat RBC was present in the circulation of all the surviving heterologously protected mice. 3. Rat serum proteins could not be detected in these mice by the serum-agar method.

Thymus specificity in lethally irradiated mice treated with rat bone marrow.

Summary Immunologic and cytologic tests indicate that the thymuses of lethally irradiated mice protected with rat bone marrow are repopulated by rat-type cells. The agglutination tests showed this repopulation of the thymus by donor cells to be 100% complete 30 days after treatment, and the cytologic analysis of dividing cells showed 100% rat-type cells 21 days after treatment. Although the histologic architecture of these thymuses was often normal, recovery of the thymuses in terms of weight was incomplete.

Reduced Immune Potential of Aged Mice Significance of Morphologic Changes in Lymphatic Tissue.

Summary Hemagglutinin responding capacity to sheep erythrocyte antigen in 3-year-old BC3F1 mice was approximately 10% of the response in normal young adult mice. The reduction in primary antibody-forming capacity was determined in aged animals that had no specific lesion of lymphatic tissue such as lymphoma, lymphosarcoma, suggesting that the reduction was primarily due to unspecific atrophy or degenerative changes. Results of splenectomy in the aged mice suggest that the spleen is the major source of immunological competence in the aged animals and that the reduced immune capacity in these mice is not due simply to failing spleen function.

Preservation of Antibody-Producing Cells at Low Temperatures A Method of Storage that Allows Complete Recovery of Activity.

SummaryMethods for prolonged storage at low temperatures and recovery of antibody-producing cells from spleens of preimmunized mice were investigated. A method was devised which permits the cells to be stored with no decline in their capacity to synthesize antibodies upon subsequent in vivo culture. The method consists of suspending cells in 10% dimethyl sulfoxide, decreasing the temperature of the suspension gradually to −50°C followed by storage at −196°C. The extent to which antibody-producing cells are damaged by certain other freezing procedures was evaluated.

Significance of a Single-hit Event in the Initiation of Antibody Response

THE origin of the physico-chemical and immuno-chemical heterogeneity of immunoglobulin molecules has been a perplexing problem for many years. Recently, evidence has been accumulating which points to variability in the expression of antigen-stimulable progenitor cells as the cause of immunoglobulin heterogeneity. Whether or not this is the case—or whether, for example, the variability may result from non-uniformity of polypeptide chain construction by polysomes—can only be decided when methods are available for analysis of immuno-globulins at various times during response by the progeny of a single precursor cell. Before such clonal investigations can be attempted, it is obviously necessary to have some clear notion about the number and frequency of these precursor cells. This communication presents the results of experiments designed to enumerate such cells in spleen cell suspensions from non-primed and primed mice of two different hybrid strains of various age groups.

ANTIGENS RESPONSIBLE FOR BONE MARROW TRANSPLANTATION IMMUNITY

The antigens responsible for the bone marrow transplantation immunity were determined by sensitizing the mice 2 or 6 weeks prior to the 950 r and rat bone marrow transplantation (950 r-RBM). Indicative of the sensitizing antigens was the increased mortality 15 and 30 days after 950 r-RBM in comparison to the nonsensitized 950 r-RBM mice. Sensitizing antigens were absent in the serum and red blood cells, but present in nucleated cells. They were localized in the nucleus, mitochondria, and microsomes in a reasonable concentration and in the supernatant fraction in a relatively low concentration. The antigens of the mitochondria and microsomes were resistant to nuclease and protease treatment. The nuclear antigens were resistant to ribonuclease and papain treatment, and slightly susceptible to trypsin. The antigenicity of desoxyribonucleasetreated nuclei was variable. (auth)

Effects of immunized parental strain bone marrow on lethally irradiated F1 hybrid mice.

Summary Pre-sensitization of parental strain donor mice against F1 hybrid recipients accentuated the foreign bone marrow reaction caused by injection of parental marrow cells into lethally irradiated F1 recipients. This effect occurred with use of parental strains (101 and C3H) that were histocompatible at the H-2 locus, as well as with those (C57BL and 101) that were histoincompatible at this locus. These results are interpreted to indicate the importance of relative antibody-forming potency of implanted cells, as well as the extent of histocompatibility differences in pathogenesis of the homograft reaction.

Persistence of heterologous bone marrow in mice as function of x-ray dose.

Summary Bone marrow from species closely and distantly related to the mouse was injected after various X-ray doses to the total body. Rat, hamster, guinea pig, and rabbit bone marrow persisted in normal, nonirradiated mice for not more than 1 day. The minimum X-ray dose that would permit persistence of rat, hamster, guinea pig, and rabbit bone marrow in mice for more than 3 days was 400, 600, 1150, and 1500 r. respectively. The minimum X-ray dose that permitted (a) temporary transplantation of rat and hamster bone marrow in mice was 500 and 600 r, respectively, and (b) prolonged transplantation of rat and hamster bone marrow in mice was 800 and 950 r. respectively. The significance of these findings is discussed.

A need for critical evaluation of automatic microtitration machines

Abstract A method for evaluation and standardization of microtitration machines using isotopically labeled protein is discussed.