Diagnostic immunology最新文献

Ninety-two slant extracts prepared from 2-week-old cultures of seven Aspergillus groups, nonsporulating "albino-type" A.fumigatus, Blastomyces dermatitidis, Histoplasma capsulatum, 3 Penicillium spp., 2 Pseudallescheria spp., 3 Paecilomyces spp., and Acremonium sp., were analyzed concurrently against antisera to A. fumigatus, A. flavus, A. nidulans, A. niger, and A. terreus. The extract of each of the aforementioned five pathogenic Aspergillus spp. produced 2-11 specific antigen-antibody complexes after reacting with its homologous antiserum. Antisera prepared against extracts to these pathogenic aspergilli demonstrated variable intra-generic crossreactivity, which were eliminated by adsorption with heterologous Aspergillus spp. antigens. Fewer nonspecific reactions were noted with the reference antigen-antibody precipitates of A. nidulans and A. Terreus than with reference precipitates of the other Aspergillus spp. Exoantigen extracts of "albino-type" isolates of A. fumigatus produced two to five specific precipitins against anti-A. fumigatus serum only. Based on the specific reactions produced by the eight albino-type isolates and 1 Aspergillus sp. isolate, all these fungi were identified correctly and placed in the A. fumigatus group. Analyses of conventionally identified A. fumigatus, A. flavus, A. nidulans, A. niger, and A. terreus including an isolate of A. parasiticus, enabled us correctly to classify them (51/51, or 100%) into their respective groups. Specific Aspergillus spp. antigen-antibody precipitates were characterized and used as references in exoantigen tests. None of the fungi in the genera other than Aspergillus produced antigens identical to the selected reference antigens.

Three monoclonal antibodies were recently produced in our laboratory that specifically identify murine tyrosinase, the enzyme critical to the production and regulation of melanin pigment in mammals. These antibodies are now shown with indirect immunofluorescence to cross-react with human tyrosinase in normal, preneoplastic, and transformed melanocytes. All epitopes specifically recognized on the mature, glycosylated form of murine tyrosinase are also present on the human enzyme, which suggests that mammalian tyrosinase is a highly conserved protein. These monoclonal antibody reagents are useful as sensitive, highly specific probes to identify pigmented human melanocytes both in vivo and in vitro.

An inexpensive, easily performed enzyme-linked immunosorbent assay (ELISA) was developed to measure specific IgG, IgA, and IgM antibodies to the common antigens Escherichia coli, diphtheria-tetanus toxoid, and tetanus toxoid. Normal values were established. Classical antibody deficiency disease states were confirmed and delineated by these assays. Additionally, several instances were discovered when functional antibody levels were abnormal when the serum immunoglobulin levels were normal. The use of ELISA assays for antibodies to common antigens provides a useful technique to measure and monitor isotype responses of the humoral immune system.

IgG subclass levels were measured by an indirect competitive immunoenzymatic assay with selected monoclonal antibodies in sera from 180 adult blood donors. Mean levels were 6.35 mg/ml (65% of the sum of the subclasses) for IgG1, 2.61 mg/ml (26.2%) for IgG2, and 0.414 mg/ml (4.3%) for IgG3. IgG4 levels were significantly different in men (mean 0.456 mg/ml, 4.8% of the sum) and women (mean 0.29 mg/ml, 3.2%), with very wide ranges. The distribution of IgG2 levels was more homogeneous than that of IgG4 but more heterogeneous than those of IgG1 and IgG3, with a number of sera that displayed low levels of IgG2.

Human effector cell function in ADCC reactions was studied as a result of observations showing discrepant ADCC reactivities among different effector cell populations. Effector cells prepared from ten blood donors were tested individually and as a pool against a battery of nine antisera-target cell combinations in an 11-x-9 matrix. The results identified individuals with weak, intermediate, and strong effector cell functions; however, there was a wide range of ADCC reactivity by each person's effector cells against the nine targets. No single antibody-target cell combination was consistently subjected to the least kill or greatest kill by the different effector cell preparations. Pooled effector cell responses were found to be weaker than expected. There was no relationship of age or sex with effector cell function, but a trend was noted for strong and weak reactions to be associated with HLA-DR7 and DR1, respectively. Neither the sharing of HLA antigens between effector and target cells nor self ADCC reactivity could account for the variations in effector cell function. Exploratory principal components factor analysis suggested that recognition of antibody-target cell combinations by effector cells was represented by three major groupings. These data collectively indicate the existence of an allorestrictive Fc receptor recognition step in ADCC responses.

Coded samples of cerebrospinal fluid (CSF) from 112 patients with a variety of neurologic disorders were investigated for oligoclonal IgG bands by isoelectric focusing followed by immunofixation. All 16 patients with probable multiple sclerosis had oligoclonal bands. All four patients with paraneoplastic syndromes having multifocal nervous system involvement also had bands, whereas five patients with lupus, three having multifocal nervous system involvement, did not show any oligoclonal bands in the CSF. This technique is highly sensitive in detecting bands in MS, whereas other disorders that produce demyelination showed various levels of sensitivity.

The technicon H-6000 has the unique ability among automated hematology systems to discriminate basophils from other hematopoietic cells on the basis of astra blue positivity of heparin-containing granules. We therefore examined the ability of this flow cytochemistry system to predict allergic diathesis in vitro by examining the number of basophils detected before and after incubation with a variety of allergens. One hundred subjects with documented atopic reactions to known allergens were examined and compared to 13 patients who had undergone successful desensitization and 12 normal subjects who had no history of atopy. One subject who had a previous anaphylactic response to penicillin but was skin-test negative to the major antigenic determinant demonstrated 55% degranulation after incubation with penicillin G. Finally, the basophil degranulation as assessed by the Technicon H-6000 was compared to a histamine release assay to determine the sensitivity of the automated system. The results suggest that flow cytochemistry may prove a valuable tool in predicting the success of desensitization therapy for common allergens and may have the potential to screen atopic reaction in the routine hematology laboratory.