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Biomedical subjects

T N Harris

Publications and source records attributed to T N Harris.

At least 19 recordsLinked to original sources
PubMed1978

Enhancement of growth of allogeneic mouse tumor by the IgG1 fraction of alloantibody preparations.

Because staphylococcal protein A binds all the known subclasses of mouse IgG except IgG1, ethanol-fixed staphylococci were used as an adsorbent to prepare IgG1 fractions of anti-BALB/c alloantibody-containing globulins and normal globulins of the same strains. The loss of more than 99% of the IgG2 as a result of this adsorption was demonstrated by immunodiffusion. The IgG1 fractions of C3H and CBA anti-BALB/c globulins were tested for their effect on growth of the BALB/c plasmacytomas MOPC-315 and MOPC-460 in C3H and CBA mice by incubation with the tumor cells before transplantation and by injection periodically thereafter into the hosts. With alloantibody-containing globulins that showed slight enhancement of growth of these tumors, or none, the IgG1 preparations caused considerable enhancement of tumor growth. Control preparations of normal C3H or CBA globulins, or IgG1 fractions similarly prepared from the normal globulins, showed no enhancing effect on the growth of these tumors.

Animals↗
PubMed1977

An improved plaque assay for mouse myeloma (MOPC 315) cells for use in studies of humoral and cell-mediated immunity.

Dinitrophenyl-bovine albumin was coupled at room temperature to sheep red blood cells in a procedure which minimized spontaneous lysis and allowed the preparation of large batches and their use for at least 3 weeks. The modified erythrocytes were used as a substrate for detecting local hemolytic plaques in agar by myeloma MOPC 315 cells, which secrete a paraprotein IgA with high affinity for dinitrophenyl ligand. Conditions maximizing the number of plaques formed by a given number of tumor cells were found to include coupling the erythrocytes at 1 mg/ml dinitrophenyl-bovine albumin with a molar ratio of about 50, and incubation with an amino-to-carboxy cross-linking agent, 1-ethyl-3(3 dimethyl aminopropyl) carbodiimide, at 2 mg/ml for 50 min. The method thus developed was employed to measure cellular and antibody-dependent immune reactions against the MOPC 315 cells. The experimental results show comparisons of the plaque technique with other measurements of tumor cell injury. The nature of the assay, which requires only 500 cells per plating, and which tests the synthetic capacity of single cells, suggests its use in experiments which limit the number of target cells, and in immune reactions causing injury, but not necessarily lysis, of the target cells.

Animals↗
PubMed1975

A preparation of Fc fragment of normal mouse IgG1 for production of rabbit anti mouse IgG1 serum.

Ascitic fluid globulins obtained by peritoneal irritation from normal CBA mice were digested with papain, and the digests were examined by gradient chromatography on CM cellulose. The classical three peaks of OD280 found by Porter with papain digests of rabbit IgG were obtained. Fraction II contained material which reacted in immunodiffusion against mouse anti-IgG. The ascending part of this peak reacted against anti-IgG1 and not against anti-TgG2 reacting material appearing at detectable levels in the descending part of this peak. A pool from the ascending part of this peak, containing Fc of IgG1 and not visibly contaminated with Fc of IgG2, was injected into rabbits. The resulting antisera were free enough of anti-IgG2 to be effective in removing IgG1 from alloantibody-containing globulins without appreciable loss of antibodies of IgG2 class, thus allowing the complement-dependent IgG2-class antibodies full expression of their titer, without competition by Ig1 class antibodies. Chromatography of native mouse globulin did not produce a similar degree of separation of Ig1 from IgG2.

Animals↗
PubMed1975

Shifts from IgG-2 class to IgG-1 class in CBA and C3H anti-BALB/c antibody.

With use of a recently developed method for determining relative levels of IgG-1 and IgG-2 class antibodies of a given specificity within an unfractionated serum, it has been possible to examine anti-BALB/c antibodies in the early and late part of an immunization with allogeneic spleen cells. At about 6 days after primary immunization of CBA or C3H mice with BALB/c spleen cells, suppressive antibodies can be measured in the sera of the animals. About half of these are attributable to IgM class, and this contribution decreases to zero by the 12th day. The remaining suppressive antibodies are of IgG-2 class and these increase in concentration until day 8 or 12, or begin to decline between day 8 and day 12. Anti-BALB/c antibodies of IgG-1 class have not yet appeared on day 6, but thereafter appear and increase in concentration. Thus, antibodies of IgG-1 class begin to appear after those of the IgG-2 class and may still be increasing after the IgG-2 class has stopped to increase in concentration, antibody of IgG-1 class is continuing to increase and may even continue to increase after IgF-2 class antibody has begun to decrease in concentration. Thus, the synthesis of IgG-1 class antibody begins later and continues later than that of IgG-2 class. The implications of this sequence for our data on various effects of anti-H-2 antibodies on retention of skin allografts are discussed.

Animals↗
PubMed1972

Studies on antibody-producing cells. IV. Ultrastructue of plaque-forming cells of rabbit lymph.

Efferent lymph of the popliteal lymph nodes of rabbits was collected 4 days after a single footpad injection of SRBC. Thin-layer agar plating was done to isolate plaque-forming cells of the lymph for electron microscope examination, and the numbers of plaque-forming cells (PFC) in cells from the lymph and lymph nodes were determined. Of 71 PFC of lymph isolated and examined, 93% were lymphocytes, most of them with signs of substantial levels of physiologic activity. The cytoplasm showed an abundance of free ribosomes and many finger-like projections. The endoplasmic reticulum (ER) was barely detectable in most of the active lymphocytic PFC, and in some, a few short narrow channels of ER could be seen. Approximately one-fifth of the lymphocytic PFC presented an appearance of senescence, with signs of degeneration: rounded cells, with amorphous nuclear chromatin, and very few microvilli. The remaining 7% of the PFC of the lymph showed an unusual combination of features: small round cells with a narrow ring of cytoplasm which, however, contained well-organized channels of ER. Such cells had been found only among PFC of peripheral blood of the rabbit. The number of PFC per million cells was higher in the lymph than in the suspensions of lymph node cells. In both the contralateral lymph node and its efferent lymph, the number of PFC was less than 1% that of the injected side.

Animals↗
PubMed1972

Preparation of dialyzable histocompatibility antigen from BALB-c mice (cell-membrane fragments-proteolytic digestion-detergent solubilization).

Histocompatibility antigens solubilized from cell-membrane fragments of BALB/c mouse spleen and liver, by Triton X-100 and butyl alcohol, were subjected to digestion by proteolytic enzymes in an effort to obtain smaller molecular species that retained antigenic activity. Digestion with both trypsin and papain yielded two antigens of smaller molecular weights that retained the specificity of BALB/c histocompatibility antigen, as determined by the inhibition of allogeneic antibodies, agglutination of BALB/c erythrocytes, adsorption-hemagglutination versus the soluble histocompatibility antigen, and suppression of the ability of BALB/c spleen cells to produce hemolytic plaques to sheep erythrocytes. The two active products of trypsin digestion were, respectively, excluded by Sephadex G-50 but not by G-75, and excluded by G-25 but not by G-50. Papain digestion yielded one active antigen that was excluded by G-25 but not by G-50, and a smaller antigen that was excluded by G-10 but not by G-15 and, as determined by gel filtration, has a molecular weight slightly lower than vitamin B(12).

Alcohols↗