William H. Taliaferro

MODIFICATION OF THE IMMUNE RESPONSE BY RADIATION AND CORTISONE

In considering the modification of the immune response by ionizing radiations or by cortisone, I shall largely limit this review to the antibody response following a single injection of a nonreproducing antigen. This limitation will avoid many of the complexities that arise during long-continued immunization and infection. Representative difficulties that this procedure enables us to avoid involve the proper assessment of recovery, the variable antigen dosage due to the continual release of antigen during infection, and the proper differentiation of the role of connective tissue cells and antibody in phagocytic immunity. I shall try to relate the various observed effects to antibody synthesis. The relevant data for such a correlation are drawn mostly from recent work on the differential sensitivity of the various parts of the antibody response in the rabbit to X rays and to cortisone and on various protective measures that have been found to neutralize one or more of the suppressive manifestations of these agents. Such an attempt necessitates a critical review of the literature in some respects as contrasted to extrapolations from meager data in other respects.

Reactions to light in Planaria maculata, with special reference to the function and structure of the eyes

1. El ojo de Planaria maculata consta de dos partes: las retinulas y las c6lulas accesorias que forman la copa pigmentaria. 2. Los ejemplares normales son negativos a la luz y se orientan exactamente en un ray0 luminoso horizontal. 3. LOP ejemplares con ambos ojos extirpados son negativos a la luz, pero no se orientan. 4. Los ejemplares con un ojo extirpado no exhiben movimientos circulares. Se orientan como 10s ej emplares normales cuando se les ilumina el lado normal, per0 no se orientan cuando la iluminacih se dirige a1 lado “ciego,” a menos que se muevan hasta recibir la lux en el ojo funcional. 5. Las reacciones de 10s ejemplares con un ojo normal y la mitad posterior o anterior del otro ojo extirpada se describen en el trabajo. 6. La extirpacih de 10s ojos, a diferencia de lo que sucede a1 cortar el extremo anterior, no produce efecto sobre la marcha de la locomocih en la luz directiva o no directivtt. 7. El ojo consta de dos regiones sensoriales localizadas; la estimulacih de una e ellas causa el movimiento del animal en un sentido opuesto a1 ocupado por el lado que contiene el ojo, mientras que la estimulaci6n de la otra produce el efecto opuesto. 8. Aunque el pigmento puede localizar a la estimulacih f6tica en cierto grado, probablemente no es el principal agente localizador de la estimulaci6n fbtica, como ha indicado Hesse. 9. La localizacih del estimulo luminoso estB relacionada con la estructura y posici6n de 10s rabdomas. 10. Una vez que el animal se orienta en un rayo luminoso horizontal no recibe estimulacih orientadora hasta que abandona el eje de orientacibn.

The Course of Infection of Trypanosoma Auttoni in Normal and in Splenectomized and Blockaded Mice.

Various rodents under natural conditions harbor trypanosomes which in general produce no noticeable impairment of their hosts and which as far as have been studied bear a striking resemblance to Trypanosoma lewisi of the rat. These are generally considered separate species because of slight differences in morphology and marked specificity for their vertebrate hosts, but it seems not improbable that, as pointed out by Wenyon (I926), most if not all of them represent races of T. lewisi which have become adapted to particular hosts. Thus, the previous work on T. duttoni in the mouse, which is reviewed in Laveran and Mesnil (I912) and need not be repeated here, emphasizes the resemblance of T. duttoni to T. lewisi. Much of the work presented in this and in a subsequent paper is in accord with this general belief. On the other hand, some of it shows an unexpected divergence although this is probably quantitative rather than qualitative in character.

Asexual Reproduction of Plasmodium Knowlesi in Rhesus Monkeys

and original work, the reader is referred to the publications by Sinton and Mulligan (1933a and b) and Sinton (1934). Later, Afridi (1938) observed that the proportion of 2 broods in a given infection may be different before and after the parasite decline; that segmenters, including crisis forms, first appear during the parasite decline; that the asexual cycle may be irregular; and that seg-

Populations of Blood-Dwelling Species.

THE development of parasitic protozoan populations within a host varies characteristically in different species of host and with different species of parasite (W. H. Taliaferro, 1941). The total parasite population and its density at any given moment are the result of the interplay, on the one hand, of various factors involving the invasiveness of the parasite, such as reproductive capacity and ability to become acclimated to the specific defensive mechanisms of the host and, on the other hand, of various innate and acquired factors of host resistance or susceptibility. Technical difficulties have limited most of the work on this subject to protozoa which live more or less evenly distributed in the blood stream since they can be extracted from the blood for study without sacrificing the host. Before discussing the actual infections, some of the difficulties in measuring the rate of reproduction of the parasitic protozoa and a common misconception should be emphasized. While a parasite is within a host, there is no direct method of measuring its reproductive rate comparable in accuracy to the rates determined, for example, in single cell isolation cultures of ciliates. Many authors, in measuring reproductive rates of the parasites, tacitly assume that all the progeny produced by reproduction survive and hence, that the rate of accumulation in the host gives a true rate of reproduction. All measures of the rate of reproduction have to be independent of the number of parasites which perish, however, since in malaria where it has been studied and, probably, in all cases most of the progeny die even under optimum conditions.

Effect of 5-Bromodeoxyuridine on the Hemolysin Response in Rabbits.∗:

Summary The analogue, 5-bromodeoxyuri-dine, when injected intraperitoneally within an hour and a half of an intravenous injection of sheep red blood cells, produced an unequivocal adjuvant effect on the hemolysin response in unirradiated rabbits as gauged by high peak titer. It was, however, ineffective when injected 2 days after the sheep red cells into unirradiated rabbits and did not modify X-ray-induced enhancement or depression when it and the antigen were injected one day before and one day after 400 R, respectively.

Anemia following Splenectomy in White Rats.

Numerous European workers have observed that rats frequently develop a severe anemia following removal of the spleen. That this is not always the case, however, is shown by the fact that in certain laboratories splenectomy of rats has not been followed by anemia. Lauda 1 made an extensive study of this problem and found that in approximately 75% of his splenectomized rats, a very severe hemolytic type of anemia developed. He proved it to be of an infectious nature and transmissible to other splenectomized rats. Shortly afterward, Mayer, Borchardt and Kikuth, 2 in repeating Laudas work, observed within 24 to 48 hours after splenectomy, small rod-like or dumb-bell shaped inclusions in the erythrocytes. These later increased in numbers until at the height of the anemia there were 12 or more within each erythrocyte, appearing with the Giemsa stain as reddish coccobacillary forms. They concluded that these inclusions were identical with the ones observed by Mayer 3 in 1921 and named Bartonella muris ratti because of their similarity to the inclusions found in the erythrocytes of patients with Oroya fever. We have similar findings in white splenectomized rats. The effect depends primarily upon the source from which the rats were obtained. In 13 rats recently obtained from the Wistar Institute and the Albino Supply Company stock, we have found that no significant anemia follows removal of the spleen. In 2 Wistar rats, however, which had been in the animal room for several months, splenectomy was followed by a very severe anemia. We splenectomized 11 rats obtained from Chicago dealers and in every case, usually about the fifth day, a marked anemia has developed. This anemia appears to be identical with that described by Lauda as “the infectious anemia of rats.”