Antibodies to surface IgM and IgD increase the expression of various class II antigens on human B cells

Antibodies to surface IgM and IgD were found to induce increased expression of class II antigens on normal and neoplastic human B cells within 24 h of stimulation. Antigens associated with different class II sub-locus genes (DC, DR and SB) were all found to be increased as determined by monoclonal antibodies (Leu-10 and B 3/4 for DC, D 1/12 for DR and MHM4 for SB-associated antigens). The increased expression of class II antigens was selective as anti-immunoglobulins failed to increase expression of other surface antigens such as B1 and beta 2-microglobulin. The effect of anti-mu and anti-delta could be blocked specifically by corresponding myeloma proteins suggesting that antibodies to surface IgM and IgD, respectively, were responsible for the effect observed. Moreover, antibodies to another surface antigen (B1) failed to induce such changes. Increased class II antigen expression appeared to be dependent on protein synthesis, and early changes in ion fluxes, but could not be elicited by membrane depolarization as reported in murine systems.

Surface IgG subclasses in human B cell lymphomas as revealed by monoclonal antibodies

IgG subclass expression on cells from lymph node biopsies of 17 sIgG positive B cell lymphomas has been studied. Subclass specific monoclonal antibodies were used in an immunoradiometric assay. Ten were also tested by immunofluorescence using a biotin-avidin system. Thirteen of the lymphomas expressed IgG only, while four co-expressed other Ig isotypes. Morphological investigations revealed that 14 lymphomas originated from germinal centre cells. IgG1 was found to be dominant subclass in 10 lymphomas, IgG3 in seven, IgG2 in one, while none expressed IgG4. Multiple IgG subclasses could not be detected in any of the lymphomas tested.

Modification of the 'dividing bradycardia' by hypoxia or exercise

The oxygen-conserving efficiency of the physiological adjustments to diving depends on two factors: (1) the rate of onset of reflex action, and (2) the extent to which circulating blood is withdrawn from the organs which are not irreparably damaged by transient hypoxia. We report a study in which either hypoxia or exercise has been imposed as an additional stress on human subjects performing apneic face immersion in order to determine any early changes in the reflex rate of onset and/or the final level of cardiovascular adjustment. It is concluded that the rate of onset of the diving reflex varies with the stresses imposed whereas the final level of adjustment does not.

Thyroid antibodies in blood donors: prevalence and clinical significance

In sera from 1643 randomly selected blood donors examined in 1979 thyroglobulin antibodies (TGA) were found in 3.4% and thyroid microsomal antibodies (TMA) in 7.0%. TMA, but not TGA, showed significant sex and age relationships. Eight-two donors with TMA titres greater than or equal to 1600 and/or TGA titres greater than or equal to 128 were available for a follow-up study in 1982. In 69 of these with TMA there was a significantly increased incidence of pathological thyroid function-test values (T4, T3 and TSH) as compared to age- and sexmatched donors without thyroid antibodies. In this group 9 individuals had overt and three latent hypothyroidism, two individuals were found with symptomless autoimmune thyroiditis and one with a non-toxic nodular goitre. Only 2 of these had been diagnosed before 1982, and none recognized before 1979. In addition, the group contained 9 individuals who had been treated because of hyperthyroidism, all except one before 1979. The likelihood of detecting a previously unrecognized hypothyroidism increased with increasing TMA titre. In contrast, the 24 donors with TGA did not show an increased frequency of pathological thyroid function-test-values in 1982.