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V Vetvicka

Publications and source records attributed to V Vetvicka.

29 records · Page 2Linked to original sources
PubMed1993

Effect of ambient temperature on phenotype and functions of professional phagocytes of athymic nude mice.

Cytofluorometric analysis of surface marker expression was performed on myeloid cells isolated from bone marrow, spleen and lymph nodes of nude mice and nu/+ and +/+ mice (haired controls) exposed for various time periods to ambient temperature of 22 degrees C or 28 degrees C. A rise in the proportion of cells bearing macrophage markers (MAC-1, MAC-3 and F4/80) in the spleen and of FcR+ cells in all tissues tested was found in 22 degrees C-exposed nudes with high nonshivering thermogenesis. Numbers of MAC-1+ macrophages and actively phagocytic cells increased also in peritoneal exudates. There was a conspicuous predominance of large macrophages in the exudates and the specific markers decreased in density on their surface. Ia expression declined in all tissues tested with the length of exposure to cold. In the granulocytic series (BP-2+ cells), there was a decrease in the bone marrow and lymph nodes and an increase in the spleen and circulation, which suggested an enhanced mobilization and increased production at extramedullary sites in cold-exposed nude mice. The changes in haired mice were negligible.

Animals↗
PubMed1993

Evolution of immune reactions.

The history and evolutionary pathways of defense reactions among various forms of life are reconstructed. The vertebrates evolved step-by-step from their invertebrate ancestors living in the distant past. The ancestry of vertebrate defense mechanisms must be traceable to them because these functions cannot be considered separately from the common evolutionary schema. The first part of this survey is therefore devoted to the description of major defense reactions and achievements in invertebrates. Particular emphasis is given to the taxa of present-day invertebrates most likely to exhibit some relationship to the chordates and thus to show real traces of vertebrate immune patterns. The second part involves three key assemblages of deuterostomate animals--the echinoderms, the nonvertebrate chordates, and the first vertebrates because these animals are believed to have created the prerequisites for transition from the invertebrate type of defense to the vertebrate type of adaptive immunity.

Animals↗
PubMed1993

Effect of ambient temperature on immune functions of athymic nude mice.

We performed cytoflourometric analysis of the expression of various T and B surface markers on lymphocytes isolated from bone marrow, spleen and lymph nodes of nu/nu and +/+ mice kept at 22 or 28 degrees C for various time intervals. In bone marrow of nu/nu mice the cold exposure decreased the expression of sIg and CD4 molecules and increased expression of MHC class II antigens. In the spleen, the numbers of MHC class II and sIg expressing lymphocytes continually decreased with the length of cold exposure. At the same time, the number of CD4+ cells increased. The most pronounced changes in lymph nodes were observed in the expression of CD5 antigen. The values obtained from euthymic mice kept at cold temperature were always comparable to those found in mice kept at 28 degrees C. Exposure to lowered temperature caused in nu/nu mice also significant changes in appearance of subpopulations of cells differing in size and in density of antigens. The changes did not affect the antibody response to a thymus-independent antigen.

Animals↗
PubMed1990

In vitro antigen-binding properties of coelomocytes of Eisenia foetida (Annelida).

Annelids are capable of cellular and humoral defence reactions against foreign antigens. The main aim of this study was to characterise the antigen-binding properties of coelomocytes of Eisenia foetida by means of quantitative autoradiography and direct measurement of radioactivity. It was found that the antigen-binding capacity was significantly increased after antigen stimulation. Furthermore, the preincubation of coelomocytes with non-labelled proteins reduced the binding of radiolabelled antigen. The highest level of inhibition was found when the same protein was used for preincubation. These results indicate that antigen-binding properties are to some extent specific.

Animals↗
PubMed1989

Biocompatibility of N-(2-hydroxypropyl) methacrylamide copolymers containing adriamycin. Immunogenicity, and effect on haematopoietic stem cells in bone marrow in vivo and mouse splenocytes and human peripheral blood lymphocytes in vitro.

N-(2-hydroxypropyl)methacrylamide polymeric prodrugs containing adriamycin bound to polymers via glycylphenylalanylleucylglycine side chains and, in one case, galactosamine bound via the same sequence, were tested for immunogenicity after intravenous, subcutaneous and oral application in two inbred strains of mice. The serum antibody level was determined by enzyme-linked immunoassay on the 3rd and 6th day after the last treatment. It was found that antibodies were only produced in very small amounts. In some experimental groups, the antibody titres measured following administration of copolymer conjugate were comparable with those present in non-treated controls. Attachment of adriamycin to N-(2-hydroxypropyl)methacrylamide copolymer considerably decreased its toxicity against haematopoietic precursors in bone marrow as measured by the in vivo colony-forming unit-spleen assay and its ability to inhibit [3H] thymidine incorporation by mouse splenocytes and human peripheral blood lymphocytes measured in vitro.

Animals↗
PubMed1988

Influence of interferon gamma on B cell replication.

Semisolid agar culture techniques, recombinant murine gamma interferon, (Mu IFN gamma) and monoclonal anti-Mu IFN gamma antibodies were used to evaluate the role of interferon in mitogen-dependent B cell proliferation. Subtle, but significant, effects of interferon addition were noted when unseparated spleen cells were cultured. Depending on culture conditions, the cloning efficiency of the B cells was slightly increased by optimal concentrations of interferon. When the spleen cells were cultured over unstimulated peritoneal macrophages separated by an agar spacer, and especially when no other potentiators were added to the cultures, substantial enhancement of B cell proliferation routinely resulted. The mechanism of this effect was then investigated with macrophage depleted spleen cells as well as highly enriched, positively selected, B cell suspensions. Results of these experiments indicated that B cell replication can be modulated by direct interaction with interferon and again, the conditions of culture determined the magnitude and direction of the effect. Addition of anti-interferon antibodies, indomethacin, or interleukin 1 (IL-1) to the cultures did not influence the cloning efficiency of normal splenic B cells. Therefore, we found no evidence that endogenously produced interferon, prostaglandins, and IL-1 influence B cell colony formation. Since interferon stimulated macrophages dramatically improved B cell proliferation without direct cell contact, some other monokine may be involved. Therefore, gamma interferon can participate in humoral immune responses by influencing the expansion of activated B cells directly as well as indirectly via stimulation of macrophages.

Animals↗
PubMed1986

Effects of 5-fluorouracil on B lymphocyte lineage cells.

The aim of these studies was to determine the sensitivity of B lymphocyte lineage precursor cells in mice to 5-fluorouracil (5-FU). Selective effects could be very helpful in dissecting precursor-product relationships between these and the rare multipotential stem cells from which they derive. Numbers and functions of particular types of cells were determined at intervals after a single treatment (3 mg) and, as expected, myeloid-committed stem cells were very severely affected. Day 8 spleen colony-forming cells (CFU-S) and colony-stimulating factor-responsive macrophage progenitors were reduced by 98% within 24 hr, whereas presumptive early stem cells (day 14 CFU-S) were much more resistant. B cells, which were probably recently formed in bone marrow and which are not thought to be actively dividing, were also 5-FU-sensitive, but perhaps less so than pre-B cells and immunoglobulin-negative lymphocytes bearing a B lineage marker. Approximately 5 wk were required for the normal cellular composition of marrow to return to normal. Transplantation of marrow from 5-FU-treated mice suggested that the slow regeneration of B lymphocytes might partially result from residual drug effects or damage to microenvironmental elements which are required for B lineage differentiation. Acute reductions of lymphocytes in the thymus were also documented, and the larger cells declined most rapidly and regenerated most slowly in that tissue. Of particular interest was the differential susceptibility of B cells in various lymphoid tissues to 5-FU. Whereas lymph node B cells were minimally affected, one-half of the splenic B cells disappeared within 48 hr of drug injection. Intrinsic differences in 5-FU sensitivity were confirmed by treatment of lymphocytes in vitro, and this suggests that particular B cell sets may be metabolically distinct. This drug should find additional experimental application in studies of B lymphocyte formation and functional heterogeneity.

Animals↗
PubMed1986

Intrinsic B lymphocyte and macrophage defects in C3H/HeJ mice.

C3H/HeJ mice are genetically defective in their responsiveness to lipopolysaccharide (LPS). Their B cells also have a characteristically low cloning efficiency in semisolid agar cultures, where LPS does not seem to be required. Adherent macrophages facilitate clonal proliferation in such cultures via diffusible substances. C3H/HeJ macrophages functioned poorly in this respect, and addition of normal C3HeB/FeJ macrophages to cultures of C3H/HeJ B cells did not lead to normal colony numbers. Although immune interferon can stimulate normal resident peritoneal macrophages to function well in semisolid agar cultures, it did not improve the cloning efficiency of C3H/HeJ cells. Similarly, addition of indomethacin or interleukin 1 to the cultures did not reveal that abnormally elevated production of prostaglandins or a deficiency in interleukin 1 are responsible for poor C3H/HeJ colony formation. These results indicate that C3H/HeJ mice have defects intrinsic to both B cells and macrophages that are not overcome by interferon. Purified B cells from these mice cloned poorly and did not respond to stimulation in liquid cultures with anti-mu-coated beads plus factors. There was a tendency for the poor cloning of C3H/HeJ B cells to improve with age.

Animals↗
PubMed1986

Biochemical characterization of Fc gamma receptors of mouse DCH-5 cell line.

Fc gamma receptors (Fc gamma R) were isolated from the culture medium of a mouse hybrid cell line (DCH-5) known as an over-expressor of Fc gamma R, established from a mouse adherent spleen cell and the thymoma cell BW 5147. Proteins adsorbed to insolubilized IgG were separated on Sephacryl S-200. The main fraction with maximum FcR activity was isolated and characterized as a glycoprotein with an effective molar mass of about 55 kg/mol. Under non-denaturing conditions, the protein existed as a non-covalently linked dimer. Isoelectric focussing in agarose gel showed two bands with pI = 5.2 and pI = 5.3. The amino acid composition of this fraction was similar to that of pig and human Fc gamma R, and also of rabbit FcR for polymeric Ig. The sugar composition of the fraction (about 34% w/w) resembled that of the C1q component of complement and some membrane glycoproteins.

Amino Acid Sequence↗
PubMedDate not supplied

The effects of 5-fluorouracil on immunocompetent cells depend on the genotype of experimental animals used.

A detailed study was made of the effects of 5-fluorouracil (5-FU) on primary and secondary immune responses to a T-dependent antigen in mice. Subcutaneous, intraperitoneal and intravenous applications gave similar results, oral administration was less effective. The minimal effective dose was found to be 40 mg/kg. Inbred strains known to differ in terms of IgG immune responses were compared and found to respond quite differently to the drug. For example, when 5-FU was injected 24 h before or simultaneously with antigen, IgM plaque-forming cell (PFC) responses of C57BL/10 mice were not substantially affected. In contrast, responses of A/J and Balb/c mice were suppressed 50-90% under the same conditions. If injected 24 h after the antigen, 5-FU inhibited PFC responses completely in all three strains. IgM PFC recovery was fastest in the C57BL/10 strain and started on day 7. In secondary responses, IgM overstimulation was seen in C57BL/10 and Balb/c mice if 5-FU was injected once, i.e. 24 h after primary immunization. IgG PFC were completely suppressed in primary responses in all strains. In secondary responses, the decrease was influenced by the time of drug injection and by the genotype of the treated animal. Inhibition of isotype switching was greatest in low-IgG-responding C57BL/10 mice. These results demonstrate that genotypic variation can be substantial with respect to effects of 5-FU on the immune system.

Animals↗