Studies on immune cellular injury. I. Cytotoxic effects of antibody and complement

A calcium optimum for cytotoxic T lymphocyte and natural killer cell cytotoxicity

Cytotoxic T lymphocytes (CTL) and natural killer (NK) cells are required for host defense. They destroy malignant target cells like cancer cells. Among metal cations, Ca²⁺ plays a prescinded role for CTL and NK cytotoxicity as it is the only cation used as ubiquitous second messenger. Measuring intracellular Ca²⁺ concentrations [Ca²⁺]_int in single cells has greatly changed our understanding of Ca²⁺ signaling. Yet, comparing the role of Ca²⁺ in the pre-[Ca²⁺]_int and [Ca²⁺]_int measurement era reveals that even in the pre-[Ca²⁺]_int measurement era (before 1980), the functions of Ca²⁺ and some other metal cations for the cytotoxic immune response were well established. It was even shown that Ca²⁺ influx across the plasma membrane but not Ca²⁺ release from intracellular sources is relevant for lymphocyte cytotoxicity and that very little Ca²⁺ is needed for efficient lymphocyte cytotoxicity against cancer cells. In the [Ca²⁺]_int measurement era after 1980, many of the important findings were better and more quantitatively refined and in addition the molecules important for Ca²⁺ transport were defined. The unexpected finding that there is a Ca²⁺ optimum of CTL and NK cell cytotoxicity deserves some attention and may be important for anti-cancer therapy.

STUDIES ON IMMUNE HUMAN HEMOLYSIS : II. THE DONATH-LANDSTEINER REACTION AS A MODEL SYSTEM FOR STUDYING THE MECHANISM OF ACTION OF COMPLEMENT AND THE ROLE OF C'1 AND C'1 ESTERASE

1. The inactivation, of C'1 blocks the completion of the cold phase of the Donath-Landsteiner reaction; inactivation of the other components of complement does not interfere with the cold phase of the reaction. 2. C'2, C'3, and C'4 are required for the completion of the hemolytic reaction. C'4 reacts in either the cold or warm phase, but C'2 and C'3 must react in the warm phase. 3. Partially purified C'1 or C'1 esterase can be substituted for whole serum in the cold phase, although neither reagent contains any of the other components of complement 4. Partially purified serum inhibitor of C'1 esterase blocks the effect of C'1 esterase in the cold phase, and reverses the effect of complement, C'1 or C'1 esterase when incubated with "activated" cells after the cold phase. 5. C'1 esterase activity can be eluted from "activated" erythrocytes with Na₃EDTA. 6. The components of human complement in this human hemolytic reaction act in the order C'1, C'4, C'2, C'3. Ca⁺⁺ is required for the reaction with C'1, and Mg⁺⁺ is required for the reaction with C'2. 7. Accordingly, a functional role of C'1 esterase in a human disease state is demonstrated, and a human model is established for the study of the mechanism of action of complement.

Studies on immune cellular injury. II. Functional role of C'1 esterase in immune cytotoxicity

An initial separation of reaction stages in immune cytoxicity is described. Primary isolates of normal human amnion cells were reacted first with specific rabbit gamma(2)-globulin antibody, then with human C'1 esterase in the presence of Ca(++), and finally with human C'2, C'3, and C'4 in the presence of Mg(++). Cytotoxicity, as measured by uptake of trypan blue, occurred only when these reactions were performed in the order given and did not occur when any of the constituents was omitted. Inhibition of immune cytotoxicity was achieved with partially purified preparations of human serum inhibitor of C'1 esterase under certain experimental conditions. The data are discussed in relation to the role of C'1 esterase in initiating complement action and the partial biochemical definition of an early event in immune cytotoxicity.

The localization of in vivo bound complement in tissue section

A technique has been described for the demonstration of a human complement component by an immunofluorescent method. The component detected is beta(1C)-globulin, a moiety of the third complement component, which has previously been obtained in pure form and to which a specific antiserum has been prepared. It has been shown in a model system that the binding of beta(1C)-globulin as shown by immunofluorescence is strictly equivalent to complement fixation as assessed by standard serological methods. This technique has been applied to the detection of in vivo bound complement in pathological human tissues. It was found that in vivo complement binding occurs in the lesions of several human diseases, but not elsewhere in the same tissues. In a rather limited survey of diseases that has been carried out, in vivo complement binding was found particularly in systemic L.E., various nephritides, and amyloidosis, as well as in single cases of some other diseases. The spectrum of in vivo complement binding has been compared with that of gamma-globulin binding (7S and 19S types) and with the demonstration of in vitro complement fixation and rheumatoid factor fixation. It was distinct from each of these. Rheumatoid factor fixation, detected by anti-19S antiserum showed promise as a method for the detection of antigen-antibody complexes and aggregated gamma-globulin in tissue sections. The interpretation of these findings in regard to the nature of the binding sites, and their possible significance in regard to pathogenic mechanisms have been discussed.

Antibody-induced changes in levels of cyclic adenosine monophosphate in leukaemic lymphocytes

When L2C leukaemic B lymphocytes from guinea-pigs were incubated in vitro with antibody directed to their surface immunoglobulin (Ig), a rapid rise in intracellular adenosine 3':5'-phosphate (cyclic adenosine monophosphate, cAMP) was observed. Estimation of cAMP was by a protein-binding assay using bovine adrenal protein kinase. Increases up to 30-fold occurred within 30 seconds of incubation at 37 degrees C, to be succeeded by a fall which reached the basal level between 5 and 7 min. The response was proportional to the amount of antibody present. Cross-linking of surface Ig by the antibody was necessary, bivalent (Fab'gamma)2 from the antibody gave a rise in cAMP similar to that given by the parent molecule, whereas monomeric Fab'gamma was ineffective unless it was subsequently cross-linked by anti-antibody. The rise was too rapid to have required capping of the surface Ig for its induction. Not all perturbations of the plasma membrane by antibody induce such a surge in cAMP, since anti-beta2 microglobulin, also reacting with the lymphocyte surface, failed to alter cAMP concentration. The results emphasize that immunotherapy can be influenced by antibody altering the metabolic activity of target cells, quite apart from activation of immunological cytotoxic pathways.

Auto-allergic reactions following internal irradiation of the liver

Complement fixation tests using crude liver antigen were carried out on rats following the injection of colloidal ¹⁹⁸Au calculated to deliver β radiation doses from 5000 to 10,000 rad. Marked increases in titre were recorded at doses in excess of 5000 rad. Further, tests for total haemolytic complement in ¹⁹⁸Au-injected rats at a dose of 8500 rad. showed a marked fall in serum complement. Attempts to demonstrate liver fixed γ-globulin and β_1C-complement were unsuccessful.

Separate groups were then subjected to prior splenectomy or treatment with methotrexate, an immuno-suppressive drug. The development of liver damage was observed in measurements of the serum concentration of transaminase, and complement fixing tissue antibodies, and in the histological appearance of liver biopsies.

Animals subjected to splenectomy developed more severe liver damage, whereas in those treated with methotrexate, there was evidence of amelioration of the radiation effect. The significance of these findings is discussed, and it is argued that the results provide some evidence that autoimmune processes contribute to radiation hepatitis.

Hereditary deficiency of the second component of complement (C'2) in man

Images

Cytotoxic effects produced by the beta toxin of Clostridium welchii on guinea-pigs monocytes

The cytopathic effects of Cl. welchii β toxin on guinea-pig monocytes in vitro have been studied using the uptake of eosin-Y^* as evidence of cell death.

The experiments show that these effects are due to antigen—antibody reaction probably on the cell surface, and that these reactions are not dependent on the presence of complement. Monocytes can be actively sensitized in vivo, and passively sensitized in vitro. The serum used to passively sensitize the monocytes need not possess a precipitating antitoxin titre.

Comparable experiments using an ovalbumin antigen—antibody system produced the same cytopathic effects on the monocytes as those which occurred in the β toxin—cellular system.

Tissue culture studies of lymphoid tissue sensitized to skin homografts and explanted with donor tissue

Images

Anti-nuclear factors and serum complement in systemic lupus erythematosus

Images