R.H. Van Dam

COMMON PRECURSOR MOLECULE AS ORIGIN FOR THE ECTOPIC-HORMONE-PRODUCING-TUMOUR SYNDROME

When messenger R.N.A. (m-R.N.A.) extracted from various hormone-secreting tumours was injected into Xenopus eggs, the translation products in all cases proved to be a protein of molecular weight 65 00. Analysis by polyacrylamide-gel electrophoresis and specific precipitation reactions with antibodies showed a striking similarity between the various proteins. When translation products of m-R.N.A. from calcitonin-secreting medullary thyroid carcinoma (M.T.C( and the non-secreting anaplastic form of M.T.C. were incubating with specific enzyme systems (the microsomal fraction) from both types of tumour, enzymes from anaplastic M.T.C. had no effect on the translation products, whereas enzymes from differentiated M.T.C. degraded the translation products from both differentiated and anaplastic M.T.C. The results support the hypothesis that the primary gene product of all the different types of carcinoma cell studied is a single large protein (a hormone precursor or prohormone) containing different specificities. The specific enzyme system in each carcinoma cell probably selects the specific hormone liberated from this primary protein.

In vitro stimulation of goat peripheral blood lymphocytes: optimization and kinetics of the response to mitogens and to allogeneic lymphocytes.

Abstract Experiments were performed to establish the optimal concentrations for specific and non-specific lymphocyte transformation in vitro, in cultures containing 105−106 caprine lymphocytes. A microculture system was used in conjunction with a semiautomatic sample harvester. The assay was optimized for mitogen concentration (PHA-P, Con A, PWN and LPS) and allogeneic cell number, number of responding cells, incubation time and amount of tracer. The effect of addition of serum and the cytotoxic effect of phytomitogens on cultured cells is discussed.

PRESENCE OF ANTIGEN SENSITIZED LEUKOCYTES IN CARP (CYPRINUS CARPIO L) FOLLOWING BATH IMMUNIZATION AGAINST FLEXIBACTER COLUMNARIS

Bath immunization of carp (Cyprinus carpio L) resulted in protection of fish at natural challenge. Stimulation of leukocytes derived from thymus, spleen, anterior kidney and mid-kidney of fish immunized with Flexibacter columnaris bacterin revealed the presence of antigen sensitized cells in all lymphoid tissues except the anterior kidney. After 28 days a response was obtained in thymus and spleen leukocyte cultures.

Definition and biological significance of the major histocompatibility system (MHS) in man and animals

Abstract Already for some time the major histocompatibility system (MHS) is no longer considered to be only of importance in transplantation surgery. The MHS might also partly control specific immune responsiveness. In fact, tissue antigens may serve as a marker system for individual immunocompetence. So, in veterinary relevant species, tissue typing could be an important tool in breeding and health programs. The purpose of this review is to summarize the current knowledge of the MHS in different species.

Quantification of Turkey Immunoglobulins IgA, IgM and IgG in Serum and Secretions

The immunoglobulins IgA, IgM and IgG of the turkey were quantitated in individual serum samples as well as in pooled sera. The variability of Ig levels in normal, healthy birds was quite high: IgA: mean value 0.633 mg/ml (4.0 -x - 2.5 -x); IgM: mean value 4.37 mg/ml (0.5 -x - 1.4 -x) and IgG: mean value 8.92 mg/ml (0.6 -x - 1.7 -x). Immunoglobulin levels in egg-yolk, egg-white, bile and some intraocular tissues were quantitated as well. An interesting finding was, that the forementioned variability was by far not so high with respect to IgG levels in 20 egg-yolk samples: mean value 5.1 mg/ml (0.86 x- - 1.17 -x). Though IgG and IgM could be detected in pooled turkey bile, IgA predominated in this secretion. In aqueous humor, iris tissue and vitreous body only IgG could be detected.

Optimization and kinetics of in vitro stimulation of carp (Cyprinus carpio L.) leukocytes

The optimization of a leukocyte stimulation microassay with carp (Cyprinus carpio L.) leukocytes is described. Leukocytes were isolated from the thymus, anterior kidney, spleen, mid-kidney and peripheral blood. Leukocyte cultures were stimulated with PHA-P, LPS (Escherichia coli 055: B5) PWM, ConA and PPD from Mycobacterium fortuitum. The optimum incubation temperature for leukocyte cultures differed 3.5 days for leukocyte cultures derived from lymphoid organs and 4.5 days for peripheral blood lymphocyte cultures. Leukocytes from various organ sources showed similar reactivity patterns to stimulation in vitro by different mitogens. The results of these mitogen stimulations did not present sufficient arguments in favour of compartmentation.

Flurbiprofen and immunosuppression of Trypanosoma brucei infection in the goat

Goats infected with Trypanosoma brucei and treated with the non-steroidal anti-inflammatory agent flurbiprofen, showed a marked increase in parasitaemia, followed in one of the four goats by death. The in vitro response to mitogens of peripheral blood lymphocytes and separated T- and B-lymphocytes from healthy goats treated with flurbiprofen was normal when compared with non-treated animals. T. brucei-infected goats, not treated with flurbiprofen, showed a marked immunosuppression which was mainly localized in the B-enriched lymphocyte fraction. A combination of T. brucei infection and treatment with flurbiprofen led to even more suppression, because the T-lymphocyte function was also suppressed. It is concluded that flurbiprofen first causes a rise in the parasitaemia and that this high parasitaemia is responsible for the observed immunosuppression.

Phenotyping by the mixed lymphocyte reaction in goats (LD typing)

Abstract The LD-system of the goat, as demonstrated by the mixed lymphocyte culture (MLC) was studied in related and unrelated goats. Suggestive evidence was obtained, indicating that LD determinants are under the control of gene(s) which may be in the same chromosomal region as those coding for the SD determinants.

Induction and effector phases of the immune response: Physiological and pathophysiological features

A review is given on the current state of knowledge about the induction and effector phases of the immune response. Physiological and pathophysiological features of the regulation of the immune response are discussed comparatively for both man and animals.