[The effectiveness of immunological methods in the diagnosis of leptospirosis]. / Effektivnost' nekotorykh immunologicheskikh metodov v diagnostike leptospiroza.

The effectiveness of Leptospira antigenic erythrocyte diagnosticum increases 4- to 8-fold due to the preliminary activation of erythrocytes and Boivin's antigen with 0.001-0.002 M solution of potassium periodate. ELISA with the use of conjugate based on antiglobulin serum and catalase is twice as sensitive as ELISA with conjugate on the basis of penicillinase, 3 times as sensitive as ELISA with conjugate on the basis of Leptospira hyperimmune serum and catalase and 10-20 times as sensitive as the passive hemagglutination test and the microagglutination and lysis test.

[A method of rapid indication of an antigen]. / Sposob ékspress-indikatsii antigena.

A simple and sensitive method for rapid detection of an antigen is offered. 0.025 ml of antiserum is placed on the slide, 0.025 ml of clarified extract containing the antigen added, and then 0.025 ml of intact 20.10(6) suspension of Kowan 1 Staphylococcus strain is added. When antigen-antibody complex is forming, staphylococcal cell aggregation starts. A staphylococcal reagent, manufactured by the Pasteur Research Institute of Epidemiology and Microbiology in Leningrad, may be employed, this making the method more available. The indication sensitivity is 0.2-1.25 mln cells per ml, this value depending on the bacterial species.

[Escherichia-erythrocyte diagnostic agents]. / Esherikhioznye éritrotsitarnye diagnostikumy.

The conditions of a simple and practicable method for the preparation of effective antigenic nonprotein diagnosticums on the basis of water-phenol extracts of 23 Escherichia species have been developed. The method consists in heating the mixture of erythrocytes and the antigen in a boiling water bath for 60 minutes. The diagnosticums thus obtained are 16-30 times more sensitive in the passive hemagglutination test and 4-6 times more sensitive in the passive hemagglutination inhibition test than diagnosticums prepared with the use of tannin, rivanol, as well as by the common method for the preparation of nonprotein antigens. The minimum concentration of Escherichia cells detected in the passive hemagglutination inhibition test is 0.8-1.2 million cells/ml.

Principles of constructing efficient erythrocyte immunoglobulin diagnostics.

Selection of the method of loading erythrocytes with preparations of immunoglobulins (IG) should be determined by the properties of the sensitins to be used. For the production of efficient antibody diagnostics it is advisable to use amidol while in the case of highly active and concentrated sera, amidol, CrCl3 and glutaraldehyde should be employed. The application of IgG preparations considerably enhances the sensitivity of PHAR in the indication of antigens. Immunoglobulin diagnostics on the basis of IG preparations of normal sera should be produced by means of rivanol, tannin or previously heated erythrocytes. In the multiform group of erythrocyte immunoglobulin diagnostics it is necessary to distinguish antibody and non-antibody preparations. Such a classification is justified with respect to differences in the purpose and the optimum methods of production of immunoglobulin diagnostics.

[Effectiveness of erythrocytic diagnostic reagents in indicating Shigellae]. / Effectivnost' éritrotsitarnykh diagnostikumov pri indikatsii shigell.

The possibility of the preparation of dysentery antibody diagnostic reagents on the basis of adsorbed sera is shown. Such diagnostic reagents permit to determine 200000-600000 microbial bodies or 0.0008-0.0016 microgram of the antigen per ml. The use of antigenic erythrocytic diagnostic reagents for the indication of shigellae is expedient in the second variant of the passive hemagglutination inhibition test in the following modification: immune sera should be diluted not 2-fold, but only 1.5-fold; the material to be tested for the presence of shigellae should be added to these dilutions in a double volume.

[Method of preparing erythrocytic Fc immunoglobulin diagnostic agents]. / Sposob izgotovlenniia éritrotsitarnykh immunoglobulinovykh Fc-diagnostikumov.

A new method for the nonspecific sensitization of erythrocytes with IgG by means of aqueous rivanol solution has been developed. Erythrocytic diagnostic reagents are intended for detecting reagents active against the Fc fragment of IgG (staphylococcal protein A, rheumatoid factor, Clq, etc.). This method is more sensitive than Boyden's sensitization methods with the use of chronic chloride, alizarin blue indicator. The active areas of the Fab fragment of IgG are blocked on the erythrocytic surface, which constitutes an important feature of sensitization by means of rivanol.

[Comparative evaluation of different globulin preparations and of the means for blood sensitization in obtaining antibody erythrocytic diagnostica]. / Sravnitel'naia otsenka razlichnykh globulinovykh preparatov i sposobov hemosensibilizatsii pri poluvhenii antitel'nykh éritrotsitarnykh diagnostikumov.

In comparing the hemosensitizing activity of various immunoglobulin preparations with different methods of erythrocyte loading the greatest activity and specificity was revealed in IgG isolated by means of DEAE-Sephadex A-50. The method of erythrocyte sensitization with the use of alizarin blue indicator was more advantageous in respect to sensitivity and specificity of Sh. sonnei and Newcastle indication over Boyden's, Jandl and Simmons', Bing's methods.

[Nonspecific means of increasing the sensitivity of the passive hemagglutination reaction]. / Nespetsificheskie sposoby povysheniia chuvstvitel'nosti reaktsii passivnoi gemaggliutinatsii.

The effect of some methods of preliminary treatment of erythrocytes on the PHAT depended on the sensitin náture and the method of erythrocyte load. In case of erythrocyte load with nonprotein and immunoglobulin sensitins without any conjugating agents the simulating effect of heating and periodate treatment was caused not by increase of stable sensitin binding, but by the reduction of physico-chemical resistance of erythrocytes. This effect of erythrocyte treatment permitted to increase the sensitivity of the antibodies and antigens determination. In loading the erythrocytes with the aid of conjugating agents and in sensitization with protein antigens after Boyden no stimuating effect of the treatment was noted.

[Selecting a method of erythrocyte fixation for the passive hemagglutination test according to the nature of the sensitin]. / O vybore metoda fiksatsii éritrotsitov dlia reaktsii passivnoi gemaggliutinatsii v zavisimosti ot prirody sensitina

Quantitative methods were applied to the study of the interaction of albumins, fraction I of Plague bacilli, diphtheria toxoid fractions differing by mol wt, flagellin of typhoid bacilli, 19S- and 7S-fractions of normal human, cholera horse, and paratyphoid B donkey sera with erythrocytes, fixed by 10 different methods. Fixation with acetaldehyde proved to be optimal for the binding of all the proteins, including flagellin, but the latter sensitized erythrocytes formalinized after Vainbach better. The significance of the method of erythrocyte fixation and of the nature of sensitin in the process of the erythrocyte loading without any utilization of the conjugating agents was demonstrated.

Interaction of erythrocytes with human serum proteins. II. Dependence of the process on the concentration of protein, exposure and temperature of medium.

The effect of concentration of human serum proteins, duration of contact and temperature of the medium on the process of their interaction with formalized, tannin-treated sheep erythrocytes was studied. Dependence of the process of specific haemosensitization on the enumerated factors was established. The character of the process of haemosensitization by serum proteins and its dependence on the concentration of sensitins and the duration of the contact with them can be expressed by Langmuir's equation. On the basis of limited preliminary experiments it is thus possible to define the optimum conditions for the loading of erythrocytes.