Formation of rosettes by nonspecific lymphoid cells which have adhered to antigen-antibody complexes

Rat lymph node-sheep red cell rosettes have been formed through the adherence of nonspecific small lymphocytes and larger cell types to antibody-sheep red cell complexes. Enough antibody to form a significant number of rosettes has been synthesized in cultures, containing draining lymph node cells of immunized rats, within 1 hr of incubation at 37 °C, or during overnight storage at 4 °C. This suggests that conditions which differentiate between specific and nonspecific rosette-forming cells are essential when immunocyto-adherence phenomena are utilized for the study of the specificity of the immune response.     

IL-4 (B cell-stimulatory factor 1) regulates multiple aspects of influenza virus-specific cell-mediated immunity

The effect of endogenous and exogenous IL-4 on the generation of influenza virus-specific cell-mediated immunity was examined. When added at the onset of the culture, IL-4 augmented both cluster of differentiation (CD)8+ lymphoproliferation and MHC-restricted, influenza virus-specific cytotoxicity. When added 5 or 6 days after initiation of cultures, IL-4 was highly effective at augmenting cytotoxicity, whereas no augmentation of proliferation was observed. This disassociation of the effect of IL-4 on lymphoproliferation and cytotoxicity indicated that IL-4 was providing a late signal in CTL generation. Studied at the level of CTL precursor maturation in microcultures, IL-4 was found not to increase cytotoxicity but to be required, in some cases, for the generation of cytotoxicity. Endogenous IL-4 production was observed and demonstrated to be important because neutralizing antiserum to IL-4 suppressed CTL development. In contrast to the effects of IL-4 when added later to the cultures, pulsing the lymphocytes with IL-4 before, or shortly after, exposure to antigen resulted in suppression of the CTL response. These results indicate that IL-4 has differentiative, proliferative, and suppressive effects on cell-mediated immune responses.     

On the occurrence and biology of some Antarctic Mysidacea (Crustacea)

Summary 10 species of Mysidacea were sampled during the Polarstern and Walther Herwig SIBEX cruises to the Antarctic Peninsula region from 1983 to 1986. The commonest were Antarctomysis maxima, A. ohlini and Mysidetes posthon. For these species the size and maturity stage composition as well as the length-weight relationships are given. The species considered are growing slowly and attain a long life span, M. posthon reached age class 3+, A. ohlini at least lived as long as 5 years, while A. maxima was found to be of age 5+ in the Peninsula area and probably 6+ in the Weddell Sea. The generation time of Antarctomysis species was 4 years and 3 years in Mysidetes posthon. Fecundity was low, mean number of offspring was about 13 for M. posthon and 21 for A. maxima. Rematuration was observed for the species A. maxima, indicating several spawning events during its life span. Biomass production is low for A. maxima, shown by a P/B-index of 0.98. Mortality of this species was estimated to be Z=1.1, which indicates that 33% of the specimens of an age group survive until the next year. The distribution and spatial separation of the two Antarctomysis species is discussed.     

Effects of prenatal X-irradiation: studies on the mechanism of X-irradiation-induced inhibition of microsomal enzyme development in rat liver

Exposure of pregnant rats to 25 R of x-irradiation on the fourteenth gestation day has produced in the male offspring an impairment of the development of the hepatic microsomal enzyme system which metabolizes hexobarbital. However, irradiation did not suppress the increase of enzyme activity brought about by the administration of chemical inducers (pheno-barbital). Actinomycin, on the other hand, inhibited to varying degrees both the ontogenic and phenobarbital-induced increases in enzyme activity. The effects on the enzyme system have been supported by in vivo measurements of the duration of hexobarbital hypnosis. The ontogenic increase in enzyme activity is hormone-dependent, while that following phenobarbital administration is independent of hormonal regulation as evidenced by the response in hypophysectomized or sexually immature animals. It is concluded from these results that the inhibitory effect of x-irradiation on the hepatic enzyme system is mediated through an action on the hormonal regulation of enzyme activity. Evidence for this hypothesis is discussed.     

Comparative Evaluation of Rheumatic Activity—A Study of Relationship Between Histologic Changes and Serologic Test Results in Cardiac Surgical Patients

Atrial or ventricular myocardium from patients with surgically corrected rheumatic valvular disease was studied for rheumatic lesions in 86 cases. Histologically active Aschoff bodies were found in 20 per cent of the cases. A slight, but statistically not significant relationship was demonstrated in comparison of elevated serologic tests for rheumatic activity with the presence of Aschoff bodies.