Diagnostic immunology最新文献

Monoclonal antibodies generated against human chorionic gonadotropin (hCG) were utilized in radio- and enzyme-immunoassays of this reproductive hormone in biological fluids. One of the monoclonal antibodies, beta-4D6, was shown to have extremely high affinity (Ka = 8 X 10(10) M-1)) and high specificity (less than or equal to 0.6% LH cross-reactivity) to beta-subunit of hCG and whole hCG. It was used in competitive radioimmunoassays (RIA) for the determination of low levels of serum hCG. An excellent correlation was obtained concerning the assay results between the monoclonal antibody-based system and others using conventional polyclonal anti-sera. In combination with another discrete hCG monoclonal antibody, solid-phase sandwich radiometric and enzyme immunoassays were established. These immunoassays could easily be performed, and they offer sensitivity and efficacy of hCG determination comparable to those of conventional ones.

Autologous mixed lymphocyte reaction (AMLR) was measured in 12 patients with multiple myeloma. In ten patients depressed AMLR was found. Depletion of adherent monocytes caused enhancement of AMLR in those with a normal OKT4/OKT8 ratio. Only after monocyte depletion was a high correlation found between the AMLR values and the absolute number of OKT+4-T lymphocytes in the patients' peripheral blood. There was an inverse correlation between the suppressive effect of adherent monocytes on AMLR and the patients' serum levels of polyclonal IgG and IgM. Defects in both monocytes and OKT+4-T cells might have caused the low AMLR values and perhaps played a role in multiple myeloma immunodeficiency.

Deficiencies in both cellular and humoral immunity follow human bone marrow transplantation, predisposing recipients to life-threatening infections. Peripheral blood mononuclear cells (cells of donor marrow origin) from nine patients were collected serially at 3-month intervals during the first year post transplant and evaluated for proliferation and lymphokine (gamma interferon and interleukin-2) production in vitro. Cultures of patient cells or those of normal adult volunteers were stimulated by phytohemagglutinin (PHA) in vitro, and lymphocyte blastogenesis was assayed by tritiated thymidine uptake on day 2. PHA blastogenesis for peripheral blood mononuclear cell cultures from patients post bone marrow transplant achieved normal levels 3-6 months post transplant. Supernatants produced by cells from marrow recipients (less than 12 months post transplant) had lower-than-normal IFN-gamma activity and decreased IL-2 activity. Two patients with acute graft-vs-host disease (GVHD) had persistently depressed PHA blastogenesis, IFN-gamma production, and IL-2 production at 12 months post transplant.

B-cell functions were investigated in a well-defined high-risk group for the development of AIDS/AIDS-related complex (ARC). Stimulation of mononuclear cells (MNC) with T-cell-independent polyclonal B-cell activators failed to increase high spontaneous IgG levels observed in vivo and in vitro. The secretion of IgM following stimulation with Klebsiella M (Klebs M) or Salmonella (Salm) membrane preparation increased by a factor of 4 to 6 and thus ranged between the results of the control group and those of AIDS/ARC patients; the response to a T-cell-independent B-cell mitogen, Staphylococcus aureus Cowan I (SAC), showed profound abnormalities as well in this group. This indicates that functional B-cell abnormalities can be seen in addition to T-cell dysfunctions in patients at increased risk for the development of AIDS/ARC.

Systemic lupus erythematosus (SLE) is a multisystem disorder accompanied by a diverse spectrum of serum autoantibodies. Antibodies to double stranded DNA (dsDNA) are considered to be the most specific marker for this disease. In this study the results obtained from three different assays for dsDNA are compared: an indirect fluorescence antibody assay (IFA), a radioimmunoassay (RIA) and, an enzyme-linked immunosorbent assay (ELISA), on 57 SLE sera and 28 Sera from other disorders. Correlation of these anti-DNA results are made with C3, C4, and antinuclear antibody (ANA) titers. Our results show the IFA assay is the most sensitive and the least specific of the three tests. The RIA was found to be the most specific and was approximately as sensitive as the ELISA. We also found significant inverse correlations between anti-dsDNA levels and circulating complement levels among SLE sera for all three assays. ANA titers were significantly correlated with all anti-dsDNA assays as well. However, these anti-dsDNA assays show only modest differences explainable by numerous mechanisms. Hence, a clearly superior anti-dsDNA method does not emerge from our study.

Cancer patients are frequently immunodepressed and this could be related to undernutrition, particularly in gastrointestinal (GI) neoplasia. We therefore looked for correlations between different leucocyte subsets' (T11+, T4+, T8+, B1+, and Mo2+) cells in the peripheral blood of these patients and their nutritional state. Significant alterations were found in absolute number/ml of T11+, T4+, B1+, and Mo2+ cells. Malnourished cancer patients were more affected than those appearing well-nourished, exhibiting a decrease of 50% in the number of T11+, T4+, and B1+ cells as compared with healthy controls. The phytohemagglutinin A (PHA) stimulation index (SI) was also significantly decreased in the malnourished group. Linear regression analysis between SI and these leucocyte subsets revealed that only the T4+ cells offered a significant correlation (r = 0.6169 p less than 0.01). These results suggest that the absolute number/ml of T4+ cells reflects the nutritional state of patients bearing GI tumors.

A comprehensive comparative analysis of lymphocyte populations, natural killer cell activity, and interleukin-2 (IL-2) and interferon production was performed on cord blood and adult peripheral blood mononuclear cell populations. Analysis of the cell types present demonstrated significantly lower percentages of T3+, T8+, and Leu 11+ cells for the cord blood samples compared to the adult samples. Also, both natural killer cell activity and gamma interferon production were significantly lower in the cord blood group. These findings may correlate with the increased susceptibility of young infants to infection. Differences between the two groups were not evident for the percentages of T4+ cells, B cells, and large granular lymphocytes. IL-2 production by cells stimulated with concanavalin A and a phorbol ester was higher in cord blood. Individually, half of the cord blood samples contained more IL-2 than any of the adult samples. This result could be caused either by greater production of IL-2 by the cord blood samples or by greater utilization of IL-2 by the adult samples.

Much effort is being expended to detect and to characterize the multiplicity of antibodies directed against extractable nuclear antigens in connective tissue diseases. Hemagglutination and counterimmunoelectrophoresis are highly sensitive but lack specificity and must be followed by double diffusion. Double diffusion, however, suffers from lack of sensitivity and often from lack of clarity for interpretation of the resulting precipitin lines. We describe here a modified counterimmunoelectrophoresis procedure utilizing offsetting wells, followed by diffusion, which provides the clarity of precipitin lines for easy interpretation as well as overnight interpretation and the use of small amounts of reagents.

We studied the serodiagnosis of human hydatid disease using the dot-enzyme-linked immunosorbent assay (dot-ELISA) and the indirect hemagglutination assay (IHA). Hydatid cyst fluid antigens from sheep were highly reactive against a battery of positive human sera. Moose-derived antigen was less reactive, whereas human- and camel-derived antigens showed nonspecific false-positive reactions. Sensitivity of the Dot-ELISA was 96% using sheep-derived antigen and 45 human sera from 43 surgically proven cases of hydatidosis disease caused by Echinococcus granulosus, E. multilocularis and E. vogeli. The IHA test reacted with 100% of patient sera (P = N.S.). Specificity of the dot-ELISA was 98%; one false-positive reaction was observed in the dot-ELISA when 52 sera from healthy subjects were assayed. Cross-reactions were observed with sera from patients with cysticercosis, filariasis, toxocariasis, trichinosis, visceral larval migrans, and liver cirrhosis. Of 204 sera tested in duplicate, 191 (94%) did not vary more than one twofold titer dilution. The dot-ELISA is rapid and as sensitive as the IHA test in the diagnosis of hydatidosis. In addition, unlike other currently performed tests for hydatid disease, this rapid and economical enzyme immunoassay is very antigen-conservative, requiring only nanogram quantities of parasite antigen, and very serum conservative, needing only 50 microliter of diluted patient serum.