Search

Whilst the ability of isoantibodies to agglutinate mouse red cells in saline medium does depend in part upon the properties of the antibody molecules, the concentration of antigen upon the red cell and certain genetically determined properties of the cell surface are of even greater importance. The red cells of mice of any strain will give positive results in the human serum:dextran system whilst reactions in a saline medium are unusual. In this paper the term ‘incomplete antibody’ is used to denote antibodies that can only be detected in conjunction with other antibodies in the human serum:dextran system. The time of appearance of antibodies to homografts of an ascites sarcoma, an ascites leukosis and a solid mammary carcinoma has been studied. Incomplete antibody as defined above has been detected by two methods. In the blocking test incomplete antibody is allowed to react with red cells before contact with complete antibody, a positive result being observed as a fall in titre when the treated red cells are subsequently exposed to complete antibody. In the second type of test, the synergic test, incomplete antibody is mixed with suitably diluted complete antibody and fitrated against suitable red cells, a positive result being a significant rise in titre as compared with complete antibody mixed with normal serum. Antibodies produced by the antigen donors did not give significant blocking or synergic effects. Incomplete antibodies are sometimes detectible on the third day and with regularity on the fourth day. Antibodies ‘complete’ for A strain red cells may appear at any time from the fifth day onwards. There is sometimes a drop in fitre of varying duration on the sixth day. This corresponds with the commencement of marked inflammatory changes on the graft bed. The maximum titre is attained at about two weeks. Antibodies may disappear in under three months or persist as long as a year. The function of antibodies in homograft reactions varies with the target tissue. However, they appear before the onset of anatomical signs of homograff response regardless of the type of target cell. [ABSTRACT FROM AUTHOR]

Normally circulating human leucocytes were found to consistently lyse rabbit erythrocyte (RRBC) target cells within 24 hr in culture. The reaction is referred to as the naturally-occurring cell-mediated cytotoxic, or NOCC, reaction. Characteristics of this cytotoxic reaction are as follows. (i) The cytotoxic reaction described here can be distinguished from the antibody-dependent cellular cytotoxic (ADCC) reaction as conventional Fc receptors do not appear to play a role. Although the cytotoxic reaction occurs optimally in medium fortified with normal human serum to a final concentration of 1%, neither antibodies nor immunoglobulins in general appear to play a role. Agamma human serum or purified human Serum albumin without detectable immunoglobulins are as capable of facilitating and sustaining the NOCC cytotoxic reaction as is normal human serum. Furthermore, foetal calf serum, which promotes the ADCC cytotoxic reaction, inhibits the NOCC cytotoxic reaction. (ii) The NOCC reaction is not a phagocytic one as phagocytosis of the RRBC could not be detected during the culture period. (iii) Monocytes and neutrophils, but not lymphocytes, are capable of lysing the target cells in the NOCC reaction. The effector mononuclear cell is a monocyte with receptors for Fc and C′3. (iv) The NOCC cytotoxic reaction is dependent upon direct effector cell-target cell contact and not upon soluble mediators secreted by the effector cells since third-party bystander erythrocytes are not lysed in the presence of rabbit erythrocyte target cells and human mononuclear cells. Supernatants from lysed RRBC target cells could not lyse fresh RRBC. It is concluded that the NOCC cytotoxic reaction utilizing rabbit erythrocytes as target cells permits the identification of cytotoxic subclasses of monocytes and neutrophils. [ABSTRACT FROM AUTHOR]

A method for the isolation of large numbers of almost pure human eosinophils from peripheral blood using hypaque-ficoll density gradients, gelatin sedimentation and carbonyl iron is described. Eosinophils were obtained from patients with parasitic infections, allergic reactions, undiagnosed eosinophilias and normal volunteers. Erythrocyte (E) and erythrocyte-antibody-complement (EAC) rosettes were formed by a number of eosinophils. [ABSTRACT FROM AUTHOR]

A sensitive indirect haemagglutination technique is described which depends upon attachment of the protein antigen to the erythrocyte with difluorodinitrobenzene. The attachment of human gamma globulin to human erythrocytes has been thoroughly studied using sera containing the Rose-Waaler factor as the agglutinator. It has also been shown that horse and rabbit serum proteins and egg white may be attached to cells by the reagent. The technique is simple and sensitive but an absorption step is necessary to remove a non-specific agglutinin to cells which have been treated with the reagent. [ABSTRACT FROM AUTHOR]

Certain sera from individuals receiving large doses of penicillin have been found to contain a factor which can cause agglutination of human red cells sensitized with penicillin. Such sera were detected by a preliminary white tile screening technique and subsequently titrated in tubes. The haemagglutinating factor appeared to be heat stable (56·0° for 6 hours at least) and active over a pH range of approximately 4·8 to 9·0. In the presence of complement certain strongly positive sera caused haemolysis of the red cells. The addition of penicillin inhibited the haemagglutination reaction but this effect was reversible by the addition of penicillinase. Certain agglutinating sera gave positive complement fixation tests but no visible precipitates were obtained by tube or double diffusion agar gel techniques. Attempts to obtain active eluates from agglutinated sensitized cells were unsuccessful. It was also found that the haemagglutinating factor did not appear to have any inhibiting effect on the bactericidal action of penicillin. Starch-gel electrophoresis of positive sera demonstrated haemagglutinating activity in two pre-albumin zones. One such zone, pre-albumin-2, has been shown to be acidic-alpha-I-glycoprotein whereas the nature of pre-albumin-I remains obscure. In twenty-two of twenty-three sera so tested agglutinating activity was confined to these two zones. In the remaining serum, in addition to activity in the two pre-albumin zones, positive agglutination of sensitized cells was also brought about by the gamma-globulin fraction, and this serum was the only one which gave a positive antiglobulin test. The interpretation of these electrophoretic findings is not altogether clear and requires further elucidation. [ABSTRACT FROM AUTHOR]