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This article presents abstracts of the papers presented at the Fifth Meeting of the Scandinavian Society for Immunology, which took place from May 29-31, 1974, in Copenhagen, Denmark. A culture technique is described that allows the primary antibody response by chicken spleen cells to sheep erythrocytes (SRBC), determined as direct plaque-forming cells (PEC), to be investigated. Mixed lymphocyte culture and the elimination of responding cells with bromodioxyuridine and ultraviolet light with a subsequent restimulation were used to study the development of specifically recognizing T lymphocytes.

In this paper we present in detail the very rapid and sensitive Millipore filter assay technique for measuring tritiated thymidine incorporation during semiconservativé DNA synthesis in human peripheral blood leucocyte cultures. Leucocytes which have been incubated with tritiated thymidine are trapped on a Millipore filter which is then suitably washed and dried. The filter is then immersed in scintillation fluid in a double-vial apparatus designed to ensure a reproducible counting geometry. Alternatively, the filter and its radioactive contents can be combusted to tritiated water, the radioactivity of which is then determined in a homogeneous counting system. The parameters related to the Miilipore filter assay technique are presented, and its present uses and general applicability discussed. [ABSTRACT FROM AUTHOR]

This paper considers the feasibility of automatic screening procedures for detecting malaria parasites in blood smears prepared in the field. A simple programme for pattern recognition by computer has been developed for thin blood films that identifies parasites as densely stained particles within an erythrocyte. The parasites are detected correctly, but platelets falling accidentally within the outline of an erythrocyte and perhaps reticulocytes may be wrongly classified as parasites. The results indicate that automated detection of parasites is technically feasible but that the technique needs to be refined to reduce the incidence of false positives. A substantial increase in processing speed is required if the automatic procedure is to be economically feasible in screening programmes. The complexity of the equipment and the need for well prepared blood smears point to a possible use of the technique in laboratory checks but not under usual field conditions.

The addition of Tuberculin PPD to whole blood resulted in aggregation of the leucocytes. The degree of aggregation was assessed macroscopically and by two microscopic methods. The dose of PPD required to produce aggregation varied greatly between different subjects and an inverse correlation was noted between the dose of PPD needed and the Mantoux reaction. [ABSTRACT FROM AUTHOR]

Highly purified blood lymphocytes from treated and untreated patients with plasmacell myeloma were tested for the presence of *EAC lymphocytes carrying the C3 receptor surface marker using a rosette-technique and for thymus-derived (T) lymphocytes as judged by spontaneous rosette formation with sheep red blood cells. The treated patients were tested 5 weeks after a standardized 4-day treatment with melphalan and prednisolone. Untreated patients had 40-65% EAC-lymphocytes in peripheral blood while the EAC-cell level in treated patients was < 20%. A non-myeloma control group had 20-40%. The percentage of EAC-lymphocytes was correlated with different in vitro functional tests: lymphocyte-mediated lysis of target cells (Chang cell line or chicken red blood cells) treated with rabbit antibody correlated with the percentage of EAC-lymphocytes. DNA synthesis induced in lymphocytes by pokeweed mitogen (PWM) showed a biphasic dose response curve which may indicate activition of two populations of lymphocytes. A correlation was found between EAC-lymphocytes and DNA synthesis induced by a low concentration of PWM (0.1 μg/ml). The results support observations by other investigators which suggest that antibody-induced cytotoxicity requires cells in the non-T-lymphocyte population and the assumption that PWM is in part a mitogen for human bone marrow-derived lymphocytes. [ABSTRACT FROM AUTHOR]

Treatment of human peripheral blood lymphocytes with a polyvalent antiserum to human immunoglobulins causes a reduction in the electrophoretic mobility of the cells. Treatment of the lymphocytes with antisera to κ and λ chains has a similar effect, but antisera to α, γ and μ chains are only effective in this way when all antisera are mixed together. These findings point to the presence of immunoglobulin molecules on the surface of peripheral blood lymphocytes and the results are discussed in terms of the possible representation of immunoglobulin sub-units on the lymphocyte surface. [ABSTRACT FROM AUTHOR]

The red cell uptake of IgG on the basis of absorption experiments appears to be due to two populations of IgG molecules. One population is readily absorbable by red cells. The quantity of this type of IgG varies from preparation to preparation and appears to depend on the method used for preparing the IgG. It appears that this population of IgG molecules represents denatured or aggre- gated IgG, although no direct evidence of aggregation was obtained in these studies. The other population of red cell absorbable IgG appears to be proportional to the IgG concentration and cannot be depleted by successive red cell absorption of the IgG solution. A similar pattern of reactivity with red cells was found using [131I] IgM. Labelled subunits of IgM and fragments of IgG (Fab and Fc), differed from IgG and IgM in that they did not contain a population consisting of a variable quantity of readily absorbable molecules. [ABSTRACT FROM AUTHOR]

A modification of the leucocyte migration inhibition test, in which cells migrate in an agarose layer, was proposed by Clausen (1971). In the present study, this method was applied to PPD and hepatitis B antigen (HBAg), and its advantages were reassessed. From a technical standpoint, the migration in a monolayer facilitated a study of the morphology of the migrating cells. The proportion of the different kinds of migrating leucocytes was calculated and expressed as a function of the distance of migration. On the whole, 92% of the migrating leucocytes were polymorphonuclears and 8% lymphomonocytes. Three to 10% of the incubated cells were shown to migrate in the agarose layer. The surface area of the controls (migration without inhibition) was sufficiently constant and large (on the average 13 mm²) to allow a clear assessment of inhibition when antigen was added. In addition, the small requirement for antigen facilitated the use of this test in experimentation with purified HBAg. Application of the technique to clinical problems revealed that, with PPD as antigen, a highly significant inhibition was obtained in PPD skin test-positive normal individuals (0.0025

A method is described for indirect immunofluorescent staining of mouse T cells forming rosettes, involving fixation of rosettes by gluturaldehyde and staining with a rabbit anti-mouse brain serum absorbed so as to be specific for T cells. Using this technique, it was shown that about 44%, of spleen cells forming rosettes with sheep erythrocytes both in non-immunized and immunized mice, are T cells. The number of T rosette-forming cells increased about ten-fold after immunization with sheep erythrocytes. but only when serum antibody was detectable. [ABSTRACT FROM AUTHOR]