THE EFFECT OF COMBINATION WITH DIAZO COMPOUNDS ON THE IMMUNOLOGICAL REACTIVITY OF ANTIBODIES

Laboratory methods in the study of endometrial Claudin-4

Immunohistochemistry is a suitable method for the detection of proteins from the Claudin family and several antibodies are commercially available for the detection of Claudin congeners. Immunodetection of Caludin-4 in the paraffin-embedded specimens might be a useful tool for studying the role of these proteins in the cyclic transformation of the endometrium and its role in the endometrial receptivity; furthermore, other components of the junctional zone involved in the transformational process of the endometrium can be detected by means of immunohistochemistry/immunofluorescence with several polyclonal or monoclonal antibodies. The aim of this chapter is to comprehensively overview the materials and methods to perform the endometrial biopsy and to detect Claudin-4 in paraffin-embedded samples of endometrium. Additionally, the interpretation of the results is addressed.

SOME EFFECTS OF FORMALDEHYDE ON HORSE ANTIPNEUMOCOCCUS SERUM AND DIPHTHERIA ANTITOXIN, AND THEIR SIGNIFICANCE FOR THE THEORY OF ANTIGEN-ANTIBODY AGGREGATION

Small amounts of formaldehyde inhibited the precipitating activity of horse diphtheria antitoxin with toxin and of horse antipneumococcus serum with the homologous capsular carbohydrate. Approximately 1 part of commercial formaldehyde to 1000 parts of serum, acting for 24 hours, inhibited the flocculating activity completely. In both cases, the combining affinity of the treated antibody for the corresponding antigen was not demonstrably affected, as determined both by in vitro experiments and by animal protection. More intensive treatment of the antipneumococcus serum caused an apparent loss of its bacterial agglutinating activity, but on centrifugation the organisms cohered: combination had occurred, and only the spontaneous aggregation was prevented. These effects are the same as those previously described for diazo compounds, and have been qualitatively reproduced with acetaldehyde, benzaldehyde and butyraldehyde. The quantitative relationships suggest that only a few groups in the antibody molecule need be modified by formaldehyde in order to prevent aggregation; and it is probable that these are some of the free NH₂ groups of the antibody protein. In marked contrast, the combining affinity of both antipneumococcus antibody and diphtheria antitoxin for the corresponding antigens was only slightly affected by amounts of formaldehyde which sufficed to block the free NH₂ groups rapidly and almost completely. Similarly, this amount of treatment did not affect the reactivity of these two antisera acting as antigen with a rabbit antiserum versus horse serum. The integrity of the NH₂ groups is apparently not essential for the activity of these sera acting either as antigen or as antibody; and the slow disappearance of their activity in concentrated HCOH is apparently to be ascribed to some secondary reaction other than the simple addition of HCOH to free NH₂ groups. The present experiments do not support the theory that antigen-antibody aggregates are lattice-like structures built up from elementary antigen-antibody compounds because of residual specific combining groups. The aggregating activity of both antipneumococcus serum and diphtheria antitoxin was completely inhibited by procedures which did not demonstrably affect their combining power with antigen. This suggests that the aggregation of antigen-antibody compounds is a secondary, non-specific reaction. It is perhaps significant that the amount of formaldehyde which just sufficed to prevent aggregation also caused a marked increase in the solubility of the pneumococcus antibody, which could then no longer be precipitated at serum pH by dilution with water or by dialysis. This strongly suggests that the loss of precipitating activity is actually due to the increased solubility of the antibody and supports the hypothesis that the primary cause of specific antigen-antibody aggregation is the relative insolubility of the bound antibody.

CHEMICAL STUDIES ON BACTERIAL AGGLUTINATION : III. A REACTION MECHANISM AND A QUANTITATIVE THEORY

1. By the application of an absolute, quantitative microchemical method for the estimation of agglutinins, precise data have been obtained on the course of the agglutination of Type I pneumococcus by homologous anticarbohydrate. 2. Within the limitations imposed by the necessity for the agglutination reaction to take place at the bacterial surface, the reaction is shown to be analogous to the precipitin reaction and subject to the same laws. 3. The entire process of a typical instance of specific bacterial agglutination has been quantitatively accounted for on a purely chemical basis and expressed in the form of equations derived from the law of mass action. 4. Experimental verification of predictions based on the theory has shown a fundamental difference between this instance of specific bacterial agglutination and the commonly adduced analogies, and necessitated a revision of current conceptions regarding the rôle of electrolytes and of physical forces in the reaction.

Localization of antigen in tissue cells; improvements in a method for the detection of antigen by means of fluorescent antibody

Improvements in a method for the specific microscopic localization of antigen in tissue cells are described. This method employs antibody labelled with fluorescein isocyanate as a histochemical stain, the specific antigen-antibody precipitate being made visible under the fluorescence microscope. Two isomeric series derived from nitrofluorescein are described.

Effects of arsenic-azoproteins on mouse lymphoma cells in vivo; with observations on the effects of other anti-lymphoma agents, and on the susceptibility to these effects of lymphoma cells of various types

Conjugates made by coupling diazotized arsanilic acid with one or another of a variety of proteins regularly brought about the complete regression of established 6C3HED lymphomas in living mice without perceptibly harming the latter, while untreated control animals regularly died with lymphomatosis. Histologic studies made plain that the lymphoma cells promptly die in mice treated with the arsenic-azoproteins, while those in untreated control animals continue to proliferate. Various inorganic and organic arsenicals (including arsanilic acid and 4-arsonophenyldiazotate) were essentially devoid of effect on the lymphoma cells in vivo, and this proved true as well of the proteins employed (serum albumins and globulins procured from several species, casein, and ovalbumin). Mixtures of arsanilic acid and the several proteins, various sulfur-azoproteins, and a number of other substances—viz., amethopterin, chlorambucil, 6-mercaptopurine, 8-azaguanine, azaserine, 6-azauracil, 5-fluorouracil, thioTEPA, and DON, each given in maximal tolerated amounts—also failed to influence notably the course of established 6C3HED lymphomas in vivo. Although readily overcoming Lymphoma E9514 cells growing in the subcutaneous tissues of susceptible mice, the arsenic-azoproteins had little or no effect once these cells had reached the livers and spleens of susceptible hosts. Furthermore the arsenic-azoproteins had little or no effect in vivo on the cells of Lymphoma AKRL1, L1210, and L4946. The findings were considered in relationship to the respective susceptibilities of several types of lymphoma cells to other anti-lymphoma agents—notably guinea pig serum, immune serums prepared in rabbits with mouse lymphoma cells as antigens, and a variety of chemical compounds. Taken together, the observations provide proof that lymphoma cells of various types, although resembling one another quite closely in growth characteristics following transplantation in susceptible hosts, and in morphology as disclosed by ordinary microscopy, differ notably in susceptibility to the effects of the several anti-lymphoma agents.