Study of T cell subsets in patients with cutaneous leishmaniasis.

The proportion of T lymphocyte populations was assessed using monoclonal antibodies (OKT3, OKT4, OKT8) and spontaneous E-rosette tests with SRBC (for total and active TE cells) in 36 patients with cutaneous leishmaniasis subdivided according to the clinical variety. The T cell profile was normal in patients with simple cutaneous leishmaniasis of early ulcerative type whereas active TE cells and OKT4 positive cells were reduced in some cases of late ulcerative type. A significant reduction of active TE cells and of OKT4 positive cells (helper/inducer phenotype) and increase of OKT8 positive cells (suppressor/cytotoxic phenotype) was observed in peripheral blood of all patients with persistent active lesions and leishmaniasis recidivans. In patients with highly ulcerated persistent lesions a low proportion of active TE cells was also demonstrated in cellular extracts from dermal tissue. The results support the data obtained in experimental leishmaniasis that lack of helper/inducer cells and generation of suppressor T cells may be responsible for the development of chronic leishmaniasis.

Some properties of the plasma membrane of macrophages from germ-free rats.

The mobility of plasma membrane receptors for lectins concanavalin A (Con A), phytohemagglutinin (PHA), garden pea agglutinin (PSA), lentil agglutinin (LCA), peanut agglutinin (PNA), soybean agglutinin (SBA), wheat germ agglutinin (WGA), and perch spawn agglutinin (PFA), the presence of binding sites for sheep erythrocytes, the presence of Fc and complement receptors, as well as pinocytic and phagocytic activities were investigated in normal peritoneal macrophages from conventionally reared (CV) and germ-free (GF) rats. Differences varying according to the lectin used were found in lectin-receptor-complex lateral mobilities measured as a function of patch and cap formation. Germ-free-rat-derived macrophages showed a significant decrease in the average amount of SBA binding sites per cell as determined by 125I-SBA labeling. The percentage of complement- and Fc-receptor-bearing macrophages was lower in GF rats, in contrast to the higher percentage of macrophages forming spontaneous rosettes with sheep erythrocytes. The pinocytic activity as determined by the neutral red uptake assay exhibited a threefold increase in GF rat-derived macrophages in comparison to CV ones. On the other hand, phagocytosis was more intense in macrophages from conventional rats, as detected by the engulfing of CdCO3 microcrystals. Our results, together with other recent reports, indicate that the earlier opinion that the peritoneal macrophages of GF animals do not differ essentially from those of conventional ones needs to be revised.

Activity of gamma-glutamyl transpeptidase in peripheral blood lymphocytes in systemic lupus erythematosus.

In the population of peripheral blood lymphocytes from systemic lupus erythematosus (SLE) patients activity of gamma-glutamyl transpeptidase (GGTP) was lower than in healthy individuals. However, when erythrocyte-rosette forming cells (E-RFC) and non erythrocyte-rosette forming cells (non E-RFC) were separated by E-RFC method it was found that in SLE patients the activity of GGTP was increased in E-RFC and decreased in the population of non E-RFC. The altered activity of GGTP may be due to impaired surface membranes and changes in activation of these cells in SLE patients.

Ontogeny of lymphatic structures in the pig omentum.

The development of lymphoid populations in the omentum majus during the prenatal and postnatal life of the pig was studied. T lymphocytes, monocytes and mast cells were first found on the 40th day of gestation. B lymphocytes appeared on the 72nd day of gestation when the first macrophage aggregates were formed. Macrophages appeared to be the prerequisite for the formation of dense lymphatic areas (DLA's). At later stages T cells were observed only in the omentum of germfree pigs. DLA's of conventional pig omentum are filled exclusively with B cells.

Precursors of B-lymphocytes with surface IgM and their possible migration from bone marrow to peripheral lymphatic tissues.

The lymphocytes with surface immunoglobulins (sIg) represent precursors of B-lymphocytes and were studied in ontogeny of pigs by autoradiography using iodinated monospecific anti-mu, anti-gamma or anti-alpha antibodies. The earliest detection of sIgM+ small lymphocytes was at 44 days of gestation in liver, followed at 51 days in spleen and at 60 days in bone marrow, the thymocytes being sIg-negative. The first circulating small lymphocytes were detected at 38--40 days and are most probably thymus-derived.

Stimulation of fetal spleen cells with lipopolysaccharides.

LPS proved to be good B-cell mitogen for fetal pig spleen cells and induced proliferation as well as differentiation of virgin resting small lymphocytes within 48 hours of cultivation. The LPS-activated lymphocytes and blast-like cells were more intensely labeled with anti-Ig antibodies than control cells, most probably due to an increased density of surface Ig. A lower percentage of LPS-activated cells was found to be labeled with F(ab)2 fragment of anti-L than with anti-L antibodies having an intact Fc fragment. The latter finding suggests non-specific binding of antisera to Fc receptors which appear to be activated on LPS-stimulated lymphoid cells.

Identification of T and B lymphocytes in pigs by combined E-rosette test and surface Ig labelling.

A procedure for combining labelling of B lymphocytes with [125I]anti-Ig-antibodies and E-rosetting is described which permits simultaneous detection of B lymphocytes and T lymphocytes. Pig lymphocytes were incubated with iodinated anti-Ig antibodies and the E-rosette test with SRBC was performed. E-rosettes appeared stable after methanol fixation of cell smears on agarose-coated slides and treatment for autoradiography on stripping films. The percentage of cells classified as B or T lymphocytes in pig peripheral blood closely resembles that in man. No doubly marked cells were demonstrated provided cells were classified as E-rosettes only when 5 or more red cells were attached.

Surface immunoglobulins on stimulated lymphocytes.

The effect of phytohaemagglutinin, lipopolysaccharide, lipid A and streptococcal erythrogenic toxin on the expression of surface immunoglobulins on nerborn piglet spleen lymphocytes was studied, using iodinated anti-pig Ig, L-, mu- or gamma-antisera. It has been concluded that only IgM is the surface immunoglobulin on non-stimulated as well as LPS-stimulated piglet lymphoid cells. An increase in the numberof labelled cells was observed after cultivation of piglet spleen cells with all the mitogens tested.

Immunoglobulins on the surface of lymphocytes in ontogeny.

Immunoglobulins on the surface of lymphocytes from pig foetuses and newborn precolostral piglets were studied using iodinated monospecific anti-pig gamma- or mu-antisera. Labelling of cells was determined by autoradiography in light and electron microscope. Beginning with the 80th day of gestation the lymphocytes with surface IgM were detected in significant amounts in the spleen, whereas at earlier stages of prenatal development the IgM-bearing lymphocytes were detected rarely. The cells which carry surface immunoglobulins were classified as small lymphocytes with typical ultrastructural morphology.