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Biomedical subjects

R T Reese

Publications and source records attributed to R T Reese.

46 records · Page 3Linked to original sources
PubMed1978

Immunization against malaria with antigen from Plasmodium falciparum cultivated in vitro.

Aotus monkeys, which are generally killed when infected with the human malaria parasite Plasmodium falciparum, have been identified and grouped by karyotype. These animals were immunized with parasite material obtained from P. falciparum cultivated in vitro which had been maintained in culture for over a year. When sufficient amounts of this antigenic material were used with a synthetic muramyl dipeptide (MDP), protective immunity was induced without presenting the antigen in complete Freund's adjuvant.

Animals↗
PubMed1978

Control of antibody heterogeneity in strain 2 guinea pigs.

When Wright's strain 2 guinea pigs are immunized with 2,4-dinitrophenyl conjugates in complete Freund's adjuvant, the antibody response varies with the choice of carrier. Immunization with 2,4-dinitrophenyl-guinea pig albumin elicits a response that requires approximately 21 days to detect. The antibody produced is, according to isoelectric focusing, relatively homogeneous IgG2 having a neutral isoelectric point. On small amounts of IgG are produced. Stimulation of animals with 2,4-dinitrophenyl-keyhole Limpet hemocyanin produces a response by 14 days is similar to the peak response inititated by 2,4-dinitrophenyl-guinea pig albumin. With time, however, basic IgG2 populations are added to the response. By days 28-35, when the anti-hapten response has reached a plateau, the major subpopulation of antibody is neutral IgG2, but there exists several times as much basic IgG2 as IgG1. These data suggest that antigen-responsive cells may be ordered into groups having different thresholds of activation. Regardless of the strength of the antigenic stimulus, there is a set sequence of activation. The same cells always play the primary role, contributing most of the antibody regardless of whether secondary clones of cells are activated.

Animals↗
PubMed1978

Fine structure of human malaria in vitro.

The erythrocytic cycle of the human malaria parasite, Plasmodium, falciparum, was examined by electron microscopy. Three strains of parasites maintained in continuous culture in human erythrocytes were compared with in vivo infections in Aotus monkeys. The ultrastructure of P. falciparum is not altered by continuous cultivation in vitro. Mitochondria contain DNA-like filaments and some cristae at all stages of the erythrocytic life cycle. The Golgi apparatus is prominent at the schizont stage and may be involved in the formation of rhoptries. In culture, knob-like protrusions first appear on the surface of trophozoite-infected erythrocytes. The time of appearance of knobs on cells in vitro correlates with the life cycle stage of parasites which are sequestered from the peripheral circulation in vivo. Knob material of older parasites coalesces and forms extensions from the erythrocyte surface. Some of this material is sloughed from the host cell surface. The parasitophorous vacuole membrane breaks down in erythrocytes containing mature merozoites both in vitro and in vivo. Merozoite structure is similar to that of P. knowlesi. The immature gametocytes in culture have no knobs.

Animals↗
PubMed1977

Banded chromosomes of the owl monkey, Aotus trivirgatus.

Chromosomes of the owl monkey, Aotus trivirgatus, with 2n=54, 53, or 52, have been stained to show quinacrine (Q-) and Giemsa (G-) bands, and a karyotypic arrangement has been proposed based on lengths, centrometric index, and banding pattern. C-bands were present at the centromeric region of every chromosome and over the entire short arm of certain acrocentric chromosomes; 5-methylcytosine was concentrated in the same regions. Bright Q-bands at the telomeric ends of the short arms of some chromosomes probably represent a second type of repetitive DNA. Ag-staining showed that only the chromosomes bearing a secondary constriction are nucleolus organizer chromosomes.

Animals↗
PubMed1975

Anti-dinitrophenyl antibody production in strain 13 guinea pigs fed or sensitized with dinitrochlorobenzene.

Guinea pigs fed dinitrochlorobenzene (DNCB) in corn oil become unresponsive tosensitization by later percutaneous applications of DNCB in olive oil. Sera taken from animals after feeding DNCB or after feeding and intradermal stimulation with DNCB contained no antibody detectable with 2,4-dinitrophenyl (DNP)-labeled T4 bacteriophage; if any antibody was present, its concentration was below 2 mu g/ml. Guinea pigs fed DNCB and then immunized with DNP on a foreign carrier, keyhole limpet hemocyanin (KLH), produced as much antibody 16 to 18 days later as did animals which had only been sensitized by intradermal injection of DNCB in phosphate-buffered saline and then immunized with DNP-KLH. The amount of antibody produced to DNP-KLH WAS MEASURED AT INTERVALS. In the fed animals, the titer either remained approximately the same or increased with time. In contrast, the sera of sensitized guinea pigs contained a decreasing antibody titer when the first and last bleedings were compared. Isoelectric focusing was carried out with sera from DNP-KLH-immunized animals after the sera were first mixed with a radiolabeled hapten. The antibody-hapten profiles revealed that the DNCB-fed animalss contained predominatly IgG2 in their serum by the time of their initial bleedings, whereas sensitized animals still contained a considerable proportion of more acidic antibodies having marked charge heterogeneity. Equilibrium dialysis measurements onpurified antibody from fed animals indicated an average binding affinity for hapten equivalent to that of purified antibody from sensitized animals. Feeding of DNCB did not cause any obvious decrease in the number of lymphoid cells able to bind 125I-labeled guinea pig IgG. Lack of reduction of the average binding affinity coupled with the retention of antigen-binding lymphoid cells, permit the conclusion that feeding DNCB to guinea pigs under the conditions used did not induce an unresponsiveness or a deletion of those cells which have the potential to produce anti-DNP antibody. Thus, feeding of guinea pigs with DNCB in oil seems to induce a central tolerance at the T cell level with adversely affecting their B lymphocytes. The antibody response obtained by immunization with DNP conjugated to a foreign carrier is not only quantitatively equivalent to that obtained in control animals but qualitatively it appeared to be more mature with respect to charge at a relatively early time (16 to 18 days. Since the antibody levels in serum from fed animals increased or remained approximately constant with time instead of waning as occurred in the DNCB-sensitized animals, feeding or sensitization with DNCB may also have affected some cell or cell product important in the regulation of antibody production.

Administration, Oral↗