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The distribution of T lymphocytes expressing the different polypeptides of the leucocyte common antigen (LCA) family detected by CD45R and UCHL1 antibodies has been studied in normal lymphoid tissues. In the thymus most cortical thymocytes express UCHL1 and co-express CD4 and CD8. The more mature membrane CD3+ (mainly medullary) T cells are heterogeneous and may express both UCHL1 and CD45R weakly or be restricted to display CD45R or UCHLI alone. In the medulla both the CD45R+ and UCHL1+ subpopulations contain single positive CD4 and CDS cells. In tonsils, germinal centre T cells are almost exclusively UCHL1+, CD4+ and a proportion also express HNK-l (Leu 7) antigen. In the paracortical areas approximately equal numbers of CD45R+ and UCHL1+ cells are found but these separately occupy nests of cells containing one or the other type. Again, both CD45R+ and UCHL1+ cells include single CD4+ and CD8+ lymphocytes. A small proportion (<5%) of strongly CD45R+, UCHL1+ double-stained cells are also seen, and these probably represent recently activated lymphocytes. In the gut, small clusters of such strongly double- labelled cells are in the submuscular mucosae while cells of the lamina propria are almost exclusively UCHL1+. Many intra-epithelial lymphocytes are only weakly positive or negative for UCHL l and appear to be CD45R+ . These results are consistent with the view that expression of different CD45 polypeptides identifies successive stages of thymocyte-T-cell maturation and that following their thymic education, unprimed T lymphocytes are CD45R+, while primed memory T cells arc UCHL1+. These populations occupy different microenvironments. [ABSTRACT FROM AUTHOR]

This paper describes a form of red cell lysis differentiated from classical complement haemolysis by its occurrence in the absence of antibody on the cells and in the presence of EDTA. This type of haemolysis has been called reactive haemolysis. It is the result of the interaction, in the presence of red cells, of at least two serum factors called ‘reactor’ and ‘indicator’, respectively. Reactor only becomes active after incubation at 37° of serum with certain agents, notably antibody-coated bacteria, zymosan and agarose, in conditions similar to those required for complement activation. The potential for the formation of activated reactor could be demonstrated infrequently in healthy subjects but more frequently in sera from hospital patients. Activated reactor behaved as a protein sedimenting between 7S and 19S, and of α2-β1, electrophoretic mobility in agar. Indicator factors were present in all human sera studied, as well as in the sera of a number of mammalian species. They were demonstrable at high dilutions of the serum and required no prior activation for their action. They occurred maximally in the 7S fractions of serum proteins and migrated in the β2 position on electrophoresis. Reactive haemolysis was first observed and can most conveniently lie demonstrated in a red cell-agarose gel. It can also be demonstrated in the test tube following partial purification of activated reactor and indicator factors. Studies in the test tube indicated that a .soluble labile lytic factor was responsible for this type of haemolysis, [ABSTRACT FROM AUTHOR]

Certain human sera contain antibodies which under some circum- stances inhibit complement dependent lysis of sensitized sheep cells. The activity of these antibodies was demonstrated by the use of agarose plates containing sensitiized sheep cells. Most human sera placed in small holes cut in the plates produced homogeneous zones of total lysis around the holes. Occasional sera produced an inner zone of unlysed cells within an outer zone of lysis. Detailed studies of three such sera showed that this appearance was due to a protective effect of natural anti-sheep cell antibodies of IgG class. [ABSTRACT FROM AUTHOR]

Urine collected and concentrated from three individuals after tetanus toxoid immunization has been studied for antibody activity. Gel-filtration on Sephadex G-200 was used to fractionate the urine concentrates and antibody activity in the eluates was assessed by a passive haemagglutination test. Haemag­glutinating activity was demonstrated by inhibition experiments in the IgG and IgA classes of immunoglobulin but not in the IgM or IgD classes. In no case could antibody activity be ascribed to molecules smaller than intact IgG. [ABSTRACT FROM AUTHOR]

A normal adult human male was immunized with a heat-killed typhoid vaccine. The appearance of antibodies to ‘H’ and ‘O’ antigens was subsequently studied. Antibodies were identified as belonging to specific immunoglobulin classes by gel-filtration on G-200 ‘Sephadex’, followed by specific immunochemical identification using a two-stage agglutination test. Serum antibodies to ‘H’ antigen were initially of γ1M class; later the 7S γ class became predominant. γ1A antibodies were transient in appearance. Serum antibodies to ‘O’ antigen were of γ1M and γ1A classes. Urinary antibodies to ‘H’ antigen were of γlA and 7S γ classes. No antibody activity could be detected in the low molecular weight γ-globulins of urine. [ABSTRACT FROM AUTHOR]

An investigation is described of methods of isolation and purification of the high molecular weight protein (here called β2M1 globulin) which us often associated with the isoagglutinin activity of normal human serum. In the course of these experiments it was observed that ultracentrifugal concentration of this protein from serum fractions gives rise to the simultaneous concentration of two other macroglobulins (here called β2M2 and β2M3 globulins). It was found that the concentration of β2M1 globulin in normal serum is about 25-50 mg. per 100 ml. In serum from the blood of normal donors of groups A, B and O, isohaemagglutinin activity is associated with the β2M1-globulin but probably accounts for 1 per cent or less of the total β2M1-globulin concentration in serum. This activity may represent the so-called 'natural' isohaemagglutinin. The immunilogical relation is discussed of the normal β2M1 globulin to certain other members of the 'family' of immune globulins (γ globulin and β2A globulin) and to the pathological macroglobulins occurring in Waldenström's syndrome. Although rabbit antibody to β2M1 globulin cross-reacts with γ globulin, suggesting that a portion of each molecule bears antigenic groupings in common, it was found that a considerable degree of β2M1-globulin specify could be demonstrated after absorbing antisera with purified γ globulin. Attention is also drawn to the evidence that deficiency of either β2M1 globulin or γ globulin can occur independently, suggesting different cellular sources of origin. The pathological macroglobulin demonstrable in Waldernström's syndrome us closely related immunologically to normal β2M1 globulin but is often deficient in isoagglutinin activity. This immunological relation suggests to use of specific anti-β2M1-globulin antiserum as a simple means of distinguishing macroglobulin-aemia from myelomatosis or other conditions with raised levels of γ globulin. The β2M2 and β2M3 globulins are only demonstrable in unltracentrifugal concentrates of normal serum. Evidence is presented to suggest that these proteins are nevertheless present as trace components of normal serum. The solubility and electrophoretic characteristics of these proteins resemble those of β2M1 globulin, but they can be distinguished by immunological methods from β2M1 globulin and each other. Attention is drawn to the evidence that β2M2 and β2M3 globulins may also be increased in the serum of some cases of macroglobulins. [ABSTRACT FROM AUTHOR]

The IgD-immunoglobulin producing plasma cells oft human spleens have been localized with specific antisera and the type of the light chains present in each of them has been determined by sequential staining with anti-K and anti-L antisera. About 87 per cent of IgD cells have L-type light chains. This is in accord with the prevalence of L-type light chains in IgD myeloma proteins. [ABSTRACT FROM AUTHOR]

The monoclonal antibody UCHL1 identified an antigen present on most thymocytes, a subpopulation of resting T cells within both the CD4 and CD8 subsets, and on mature activated T cells. The UCHL1 determinant is also present on cells of the myeloid lineage, but not normal B cells or NK cells. Functionally, UCHL1 identifies a subpopulation of T cells which proliferates maximally to soluble antigen and provides maximum help for PWM-stimulated immunoglobulin synthesis. In contrast, the UCHL1- cells do not induce immunoglobulin synthesis and do not proliferate in the presence of soluble antigen, although both the UCHL1- and the UCHL1+ fractions of T cells proliferate well in the presence of PHA. By standard immunoprecipitation techniques and SDS page, the antigen recognized by UCHL1 was found to have a molecular weight of 180,000-185,000. Preclearing experiments using antibodies identifying the leucocyte common antigen, LCA, and the lymphocyte function-associated antigen, LFA-1, which have similar molecular weights to UCHL1, showed that the UCHL1 determinant is not biochemically related to these antigens.