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H Van Dijk

Publications and source records attributed to H Van Dijk.

46 records · Page 3Linked to original sources
PubMed1983

Effects of immunological adjuvants on the mouse complement system. I. The inability of the polyanion heparin to act as an adjuvant is paralleled by inefficient alternative complement pathway inhibition.

Interference with hemolytic complement activity by polyanionic substances was studied in relation to the ability of these compounds to act as an adjuvant for a dead listeria vaccine. Heparin appeared a poor inhibitor of the mouse alternative pathway not only in contrast to its effects on the mouse classical and the human classical and alternative pathways, but also when compared to two polyanions with known adjuvant activity: dextran sulfate and suramin. For the three polyanions mentioned a correlation between adjuvant activity and mouse alternative pathway inhibition was observed. These findings suggest a possible causal relationship between interference with alternative complement pathway activation and adjuvant activity.

Adjuvants, Immunologic↗
PubMed1983

Antigen-specific helper activity in serum of mice primed with sheep red cells II. Partial purification of the factors involved.

The nature of antigen-specific, T-cell dependent helper activity (SSHA), present in serum of mice 9 h after intraperitoneal immunization with 2 x 10(8) sheep erythrocytes, was studied in more detail. SSHA could be enriched from serum by adsorption to formalinized sheep erythrocytes, elution of the cells with a chaotropic substance, and subsequent dialysis. This resulted in an enrichment of about 900 x with a yield of 64%. Further fractionation of the material by ultrafiltration resulted in two subfractions with helper activity indicating SSHA to be composed of two factors with mol. wt's of greater than 300,000 and about 60,000. The eventual purification for the two factors was about 1650 and 2000 x respectively, and the total yield 46%. The possible relationship between the factors and factors described by others after induction in vitro is discussed. The purification procedure appears useful for the enrichment of SRBC-specific helper factors from serum.

Animals↗
PubMed1980

Determination of alternative pathway of complement activity in mouse serum using rabbit erythrocytes.

Rabbit, mouse and sheep erythrocytes expressing different concentrations of membrane sialic acid were used to study possible modes of activation of the alternative complement (C) pathway in mouse, human and guinea pig serum. Mouse erythrocytes activated only human serum, whereas rabbit erythrocytes activated the sera of all three species. Based on the observation that rabbit erythrocytes activate the murine alternative C pathway a method for estimation of alternative C pathway activity (AP50 value) in mouse serum was devised analogous to that used for human AP50 determination. The method is not very sensitive to ageing or to batch variation of the indicator cells. The AP50 value of mouse serum measured by this method is of the same order as for human and guinea pig serum. Mouse serum AP50 activity is partly determined by natural anti-rabbit erythrocyte antibodies and is sensitive to heating (15' at 48 degrees C and 4' at 56 degrees C), and to the actions of cobra venom factor, zymosan and cysteine. Strain and sex differences with respect to AP50 activities of mouse sera were observed.

Animals↗
PubMed1979

Differential potencies of corticosterone and hydrocortisone in immune and immune-related processes in the mouse.

The effects of corticosterone and hydrocortisone on the thymus, the pituitary--adrenal axis, delayed hypersensitivity, the corticosterone plasma level and the numbers of circulating nucleated and monocytic cells were investigated in the mouse. Short-term effects within 48 h after one or two corticoid injections and late effects 7 days after a regimen of 4 corticoid injections were discerned. In short-term experiments hydrocortisone was more active than corticosterone upon the induction of leukopenia and monocytopenia and the inhibition of delayed hypersensitivity. However, regarding late effects and the short-term effect on adrenal weight, corticosterone far exceeded hydrocortisone in activity. Our results could be explained by assuming two feedback-inhibition systems for glycocorticoids. The first, likely to be responsible for the changes observed for the adrenal weight and the numbers of ciruclating white cells after a single glucocorticoid injection, was shown to be expressed in a soluble factor released in the blood stream tentatively designated "glucocorticoid inhibiting factor. The factor was more readily induced by hydrocortisone but displayed a greater specificity in inhibiting effects of corticosterone. The second feedback-inhibition system, responsible for increased numbers of circulating monocytes paralleled by an enhanced delayed hypersensitivity response, was expressed in a decreased corticosterone plasma level, most probably secondary to a diminished release of ACTH from the pituitary gland. With the glucocorticoid doses we used the second feedback-inhibition system was only triggered by the more physiological hormone, corticosterone.

Adrenal Glands↗
PubMed1979

Histamine 2 receptor-mediated immunomodulation in the mouse. I. Immunomodulation by the H2 agonist tolazoline.

Tolazoline, a drug used in the treatment of hypertension, has been described as a typical H2 agonist. In this study possible immunomodulating properties of tolazoline were investigated. A single injection of tolazoline 1 day before immunization caused an effect on delayed hypersensitivity that depended on the antigen dose. The response to 10(5) and 10(6) sheep red blood cells (SRBC) was decreased, whereas the response to 10(9) SRBC was enhanced. Administration of tolazoline 4 days after immunization predominantly affected the humoral response. The IgM response was inhibited in favour of the IgG response. Low doses of tolazoline, given to animals simultaneously with the elicitation for delayed hypersensitivity, lead to a more severe inflammation. The possible involvement of suppressor cells and vessels in tolazoline action is discussed. The application of tolazoline in the immunotherapy of human cancer is suggested.

Animals↗
PubMed1979

Cellular and humoral adjuvant activity of mistletoe extract.

The adjuvanticity of the mistletoe preparation Iscador was investigated. The cellular response to sheep red blood cells (SRBC) was augmented after intracutaneous immunization with antigen and different doses of Iscador. Iscador did not change the cellular response to 2 x 10(7) intraperitoneally administered SRBC. The IgM plaque forming cell response was accelerated and followed by an augmentation of the IgG and IgA plaque forming cell response. Evidence is presented that the immunogenic and inflammatory capacities of Iscador contribute to its adjuvant activity. Both micro-organisms and soluble, filter-adherent constituents in Iscador possess adjuvant activity. The relation between the immunostimulating properties of Iscador and its anti-tumour activity is discussed.

Adjuvants, Immunologic↗
PubMed1978

Cyclophosphamide-like cellular immunostimulation induced by 6-thioguanine (Lanvis).

The possible immunostimulating effect of 6-thioguanine was studied in the mouse. It caused a dose-dependent suppression of the cellular and humoral immune response if administered 1 day before immunization. If, however, the interval between 6-thioguanine administration and immunization was extended to 5 days, a significant enhancement of delayed hypersensitivity was observed. The The enhancement occurred only after immunization with 10(6) and 10(7) sheep red cells. The analogy between the immunostimulating effects of 6-thioguanine and cyclophosphamide is discussed.

Animals↗
PubMed1977

Quantification of in vitro antibody secretion by immune spleen cells.

A simple method to study 19S anti-SRBC antibody production is described. This technique, performed by incubation of immune spleen cells, SRBC and C in the fluid phase, utilises photomeric estimation of antibody mediated haemoglobin release. The test is quicker and more accurate than the two-step haemolytic plaque assay (Jerne technique). In combination with the Jerne technique this method gives information about haemolysin production per PFC. This was maximal on day 2 and on day 6 after immunisation, and least on day 4. The steady state value was reached again at day 9. In principle this method is suitable for the estimation of IgG production.

Animals↗