New antigenic determinant (Sa) on human lymphocytes and phagocytes

Presence of antigenic determinants reacting with homogeneous IgM/kappa cold agglutinin (CA) of a new specificity, tentatively called Sa, was investigated by bithermic cytotoxicity assay and by immunofluorescence. CA Sa killed on average 38% allogeneic peripheral blood lymphocytes (PBL) and up to 74% of autologous PBL. There was preferential kill of B-PBL compared to T-PBL. Some preference toward B cells was also noted using tonsillary B and T lymphocytes. Cytotoxic activity of CA Sa against chronic lymphocytic leukemia cells of B-type was almost equal to that of potent anti-I CA and much stronger than anti-i CA. Presence of additional B-cytotoxic factor in the serum was excluded by the use of red blood cell eluate composed solely of homogeneous CA. Thymocytes and helper-type T cells from a patient with T cell chronic lymphocytic leukemia were very susceptible to the cytotoxic action of Sa. CA Sa killed 39% of monocytes, but there was almost no kill of polymorphonuclear leukocytes. Lymphocytotoxicity of CA Sa was abolished by sialyllactose and was not influenced by I-active glycoproteins. Comparison of CA Sa to CA of other specificities showed marked differences, supporting the view that Sa has new, previously unrecognized specificity.

Examination of the immunological relationship between measles virus and canine distemper virus using monospecific measles antisera

Indirect immunofluorescence titrations were performed with measles virus, the Rockborn strain of canine distemper virus (CDV), and a large plaque variant of the Onderstepoort strain of CDV (Ond-LP) using monospecific antisera prepared against either the haemagglutinin (anti-HA), the haemolysin (anti-HL), or the ribonucleoprotein (anti-RNP) of measles virus. Tests with anti-HA showed that the Rockborn strain of CDV was more closely related to measles virus than Ond-LP. The ribonucleoprotein antigens of the CDV strains were closely related to each other but were both related to and distinct from measles virus RNP. The use of measles anti-HL serum demonstrated that CDV possesses an antigenically related acetone-sensitive component equivalent to the haemolysin of measles virus. Absorption of human convalescent serum with excess quantities of acetone-fixed CDV antigens had no effect on measles-specific anti-HA, HL, or RNP activity in the serum. Absorption with measles antigens on the other hand, totally removed all measles and CDV-specific HA and RNP activity. CDV was not neutralised by any of the monospecific antisera when tested either as individual antisera or as mixtures. Our results demonstrate the occurrence of antigenic variation between different strains of CDV, they also reveal unique antigenic determinants in both measles virus and CDV.

Measles virus-specific antibodies and immunoglobulin M antiglobulin in sera from multiple sclerosis and rheumatoid arthritis patients

When rheumatoid factor in rheumatoid arthritis and multiple sclerosis sera was titrated by the fluorescent antibody method on measles virus-infected cells, there was a marked and variable drop in titer on acetone-fixed cells as compared with unfixed cells. This was accounted for by the failure of measles virus hemolysin-inhibiting (HLI) antibody of the immunoglobulin G class to bind to acetone-fixed infected cells. It was shown by staining unfixed and acetone-fixed measles virus-infected cells that rheumatoid factor in most rheumatoid arthritis sera combined with measles virus-specific hemagglutinin-inhibiting and HLI antibodies, whereas rheumatoid factor in multiple sclerosis sera combined only with HLI antibody. Rheumatoid factor of similar specificity was also observed in normal sera and occasionally in rheumatoid arthritis sera. Both rheumatoid arthritis and multiple sclerosis sera showed almost identical increases in average titer above normal of measles virus-specific fluorescent staining immunoglobulin G and HLI antibodies.

Cytotoxic activity of cerebrospinal fluids (CSF's) against lymphocytes and phagocytes: comparison of normal and systemic lupus erythematosus CSF's

Fifty cerebrospinal fluids (CSF), 24 normal, 26 from systemic lupus erythematosus (SLE) patients were tested for cytotoxic activity against human lymphocytes, granulocytes and monocytes. Normal and SLE CSF's frequently killed all 3 cell types. Lympho- and granulocytotoxins often reacted at both 4 degrees/24 degrees C, and at 37 degrees C. They were more active when no complement was added (p less than 0.01), whereas monocytotoxicity was complement-dependent (p less than 0.01). Normal CSF's more often contained cold-reacting lymphocytotoxins and SLE CSF's more often had warm-reacting monocytotoxins, but the differences were not significant (p = 0.03). Cytotoxins were easily absorbed to and eluted from lymphocytes and granulocytes, and when CSF's were toxic to both types of cells, the corresponding eluates usually retained this activity. Sometimes, only 1 type of cell was killed by the eluate, whereas cytotoxicity against another was retained by the corresponding supernatant. In SLE remarkable differences were noted between CSF cytotoxins and serum cytotoxins. The former were often more potent at 37 degrees C not requiring non-human complement. Preliminary characterization of CSF cytotoxins suggests they may be IgG, however, participation of non-Ig cytotoxic substances cannot be excluded.

Affinity for measles virus anti-haemolysin of a residual immunoglobulin M in sera of some patients with multiple sclerosis

HEp2 cells persistently infected with measles virus were treated with trypsin to remove haemagglutinin (HA) and examined unfixed or fixed in acetone by fluorescent antibody methods, comparing those sera specific for structural antigens of the virus. Staining patterns combined with the blocking of specific immunofluorescence indicated that IgG specific for measles virus haemolysin could be recognized in multiple sclerosis (MS) sera and that in some sera from which rheumatoid factor had been removed, a residual IgM (MS-IgM) was absorbed to measles virus-infected cells and showed the same specificity in blocking tests as measles virus anti-haemolysin. MS-IgM could be removed from sera by absorption with latex particles coated with human IgG and would seem to be anti-globulin with preferential affinity for anti-haemolysin.

Taurine: an essential nutrient for the cat

Cats fed a purified diet containing purified casein as the source of protein develop retinal degeneration due to the lack of taurine in the diet. To test whether cats can synthesize this sulfur amino acid from sulfate or cystine, radioisotopes of these substances were injected into taurine-depleted and control cats. Sulfate did not serve as a precursor for taurine synthesis, whereas cystine underwent only a moderate conversion to taurine. This is in keeping with the low level of cysteinesulfinic acid (CSA) decarboxylase activity in cat liver. There was no difference between the activity of CSA decarboxylase in tissues from control cats and that in tissues from taurine-depleted cats. The pattern of tissue accumulation of [35S]taurine and from [35S]cystine also indicated that tissues from taurine-depleted cats do not synthesize [35S]taurine more rapidly than tissues from control cats. The data did not indicate a difference in taurine uptake by tissues of control and deficient cats, but progressive accumulation in deficient cats suggested that the turnover rate of taurine is decreased by the deficiency. Since supplementation of the purified diet with cysteine has been found previously to be inadequate to prevent progressive taurine depletion of the retina and its subsequent degeneration and since conversion of sulfur compounds to taurine in vivo is inadequate, taurine can be considered an essential nutrient for the cat.

The reversal of phenylarsenoxide inhibition of keto acid oxidation in mitochondrial and bacterial suspensions by lipoic acid and other disulphides

1. Inhibition of pyruvate oxidation in suspensions of Aerobacter aerogenes cells and of isolated mitochondria from rat heart and liver by phenylarsenoxide is prevented by an excess of lipoic acid, whereas inhibition due to certain bivalent cations is not. 2. In both systems inhibition persists when the bacteria and mitochondria are recovered and resuspended in fresh media in the absence of the inhibitor. Persistent inhibition due to preincubation with phenylarsenoxide, but not with the metal ions, is reversed by lipoic acid and by certain other disulphides. 3. 2,3-Dimercaptopropan-1-ol prevents the inhibition of pyruvate oxidation by phenylarsenoxide and by bivalent cations in both mitochondria and bacterial cells. 4. In aerobic suspensions of mitochondria and bacteria disulphides such as lipoic acid are reduced rapidly to dithiols. Reduction is inhibited by Co(2+), Ni(2+), Cd(2+) and Zn(2+), but not by phenylarsenoxide. 5. It is concluded that the inability of lipoic acid to prevent the action of the metal ions on pyruvate oxidation is due to the inhibition of its reduction to the effective dithiol.

Psychophysiological reactivity to mental arithmetic stress in black and white normotensive men

Racial differences in physiological responses to a behavioral stressor were examined. Thirty-four Black and 42 White male normotensives 34 to 55 years old (mean age = 43.01 years) performed a mental arithmetic task while blood pressure, heart rate, and skin conductance were recorded. Compared to Whites, Blacks had significantly higher baseline diastolic blood pressure (77.93 mm Hg vs. 73.11 mm Hg) and lower skin conductance levels (11.08 microS vs. 12.25 microS). These effects persisted during performance of the mental arithmetic task. However, when baseline differences were covaried, there were no significant physiological effects associated with the task. Analysis of changes in response levels from baseline revealed a nonsignificant trend for Whites to show greater increases in systolic blood pressure than Blacks. There were no significant race or family history effects. Further, task performance did not influence the outcome. Failure to demonstrate greater cardiovascular reactivity in Blacks and all men with a positive family history of hypertension is discussed with regard to possible "survivor effects" and methodologic limitations.