[In vivo effect of Resistocell on the Phytohemagglutinin Immunocompetence Index (rabbits)]

The RST-SAS effect in normal adult albino New Zealand giant male rabbits was studied. A positive individual response in 89% of the animal and no harmful side-effects were observed, after the i.v. administration of a suitable RSTL-SAS dose. The statistical evaluation of group data showed a significative 42% increased of the IIC.PHA above the normal basal level. Thus, the RSTL-SAS could provide an unique immunomodulator agent due to its significant biological effect and the apparent lack of any side effect.

Effects of excessive dietary zinc on the intrauterine and postnatal development of mink

Dietary exposure to 1000 ppm of supplemental Zn did not result in grossly observable Zn toxicity or Zn-induced Cu deficiency in adult mink. These same concentrations did, however, produce achromatrichia, alopecia, lymphopenia and a reduced rate of growth in the offspring produced by the Zn-treated females. These mink kits also exhibited profound immunosuppression. The in vitro blastogenic response of peripheral blood lymphocytes to concanavalin A was significantly (P less than 0.001) lower in kits born to Zn-treated dams than the response of those born to control dams. The depressed immunoresponsiveness was not a permanent defect since a normal lymphocyte response was seen approximately 14 weeks after weaning and being placed on an unsupplemented basal diet. The impaired lymphocyte reactivity is believed to be the result of altered DNA synthesis in these cells and/or an inhibition of macrophage functions necessary for normal response to the mitogen concanavalin A.

Cadmium-induced suppression of the primary immune response and acute toxicity in mice: differential interaction of zinc

Four groups of 6-week-old C3H mice were injected sc with either sterile saline, 2.8 mg Cd/kg body weight, 2.8 mg Zn/kg body weight, or 2.8 mg each of Cd and Zn/kg body weight. Forty-eight hours after the initial injection, all mice received a second dose of their respective treatments plus an iv injection of sheep red blood cells. On Days 2, 3, 4, and 5 postimmunization the mice were killed. Spleen cells were used in a hemolytic plaque-forming assay for the quantitation of the primary humoral response. Although the combined administration of zinc and cadmium completely prevented the fatal effects of the cadmium (0 vs 55% mortality), zinc failed to alleviate the cadmium-induced inhibition of the humoral response.

Immune-metabolic status improvement in cancer therapy

The authors present new trends in cancer therapy and discuss the intralymphocytic regulation of cGMP/cAMP ratio. It is suggested that proimmunity therapy results in improvement of immune surveillance in neoplasia.

Morphological behaviour of lympho-myeloid organs at experimental stimulation with leukotrophine

The influence of leukotrophine on the behaviour of lymphomyeloid organs was studied in male Swiss mice aged 2 months. In the four comparatively studied groups it was shown that leukopoiesis and immune maturation was slightly stimulated by leukotrophine or protected by thiola, a radioprotective substance; the administration of both substances, leukotrophine + thiola, enhances the two actions, myelo-lymphoid leukopoiesis and cellular pyroninophilia, almost doubling them. Histochemical studies were supplemented with histoenzymatic and cytogenetic investigations.

Synergistic effects of active specific immunotherapy and chemotherapy in guinea pigs with disseminated cancer

Sewall Wright strain 2 guinea pigs bearing pulmonary metastases of the syngeneic line 10 (L10) hepatocarcinoma were treated with a vaccine composed of 10(7) bacillus Calmette-Guérin admixed with 10(7) x-irradiated L10 tumor cells beginning 10 days after tumor inoculation. Although this treatment failed to cure most of the guinea pigs of their metastatic disease, histologic examination of the pulmonary tumors in the vaccinated guinea pigs provided evidence of a cell-mediated hypersensitivity response that disrupted the normally compact architecture seen in control tumors. When a monoclonal antibody against the L10 tumor was injected i.v. to evaluate the vascular permeability of the tumors, significantly more antibody localized in tumors of vaccinated guinea pigs than in tumors of untreated controls. These results suggested that blood-borne substances could be delivered more efficiently to L10 metastases after the tumor-bearing guinea pigs had been treated with vaccine. To determine whether such increased vascular permeability would enhance the antitumor effects of chemotherapeutic agents, combined immunotherapy and chemotherapy studies were performed. Although cyclophosphamide treatment by itself did not cure L10-bearing guinea pigs, cyclophosphamide used in conjunction with prior immunotherapy increased the survival rate of animals to more than twice that of animals treated with immunotherapy alone (74 vs 33%). These results suggest that one mechanism by which active specific immunotherapy enhances chemotherapy of disseminated tumors is by rendering tumor foci more permeable to subsequently administered cytotoxic drugs.

The immune status of the rat with carcinoma of the bowel

Studies were made to determine whether rats receiving 1,2-dimethylhydrazine (DMH) to induce bowel cancer were immunologically compromised during tumour development. General cellular immunodepression was observed in DMH rats in nonspecific assays of T-cell and killer-cell (K-cell) function and later in allograft response and in vitro tumour immunity tests. B-cell levels in local lymph nodes increased significantly very late in tumour growth. It is suggested that DMH itself was exerting immunosuppressive as well as carcinogenic effects while it was administered. After withdrawal of DMH some immune faculties (tumour immunity, B-cell response) reappeared, so it is unlikely that the immune suppression observed was a result of factors produced by the developing neoplasm. There are indications that DMH administration in the rat is immunosuppressive and that tumour growth may be facilitated by this action and not by tumour reactive lymphocytic depletion or paralysis associated with blocking factors or suppressor cell production.

[The thymopause: an immunological climacteric]

The part played by the thymus and its products in conferring and maintaining immunological competence is examined. Attention is also devoted to the effect of thymic involution on the immune system, with particular reference to a fall in circulating thymic hormone. Generally speaking, this fall occurs in the 5th decade of life, which can be described as the thymopause. It is accompanied by increased sensitivity to infection and neoplasia. Two lines of intervention are suggested: the use of highly purified, selective hormone fractions after careful evaluation of the functional aspects of the immune system; employment of organ extracts containing all or nearly all the thymic hormones and peptides in an integrated form. It is felt that the second approach is more practicable today, since it permits broad-spectrum interventions through the stimulation of many mechanisms with different sequential steps, and a well-programmed biological rhythm over the course of time.

Effect of reovirus infection and dietary levels of selected vitamins on immunocompetence of chickens

The immunocompetence of 8-week-old reovirus WVU 2937-infected and uninfected chickens fed various dietary levels of biotin, niacin, choline, or folic acid was evaluated in four experiments. Antibody production to sheep red blood cells (SRBC), wattle responses to phytohemagglutinin-P (PHA-P), and wattle responses of tuberculin-sensitized chickens to bovine-purified protein derivative (PPD) were examined in five chickens per treatment. Dietary deficiencies had no effect on the in vivo T-cell immune responses to PPD, PHA-P, or humoral hemagglutinating-antibody production to SRBC. Reovirus-infected and uninfected chickens fed biotin at double the National Research Council (1977) requirement demonstrated decreased PPD responses. Lower hemagglutinating-antibody titers in the uninfected chickens and increased titers in the infected chickens were observed in those fed 200% of the requirement of biotin when compared with the chickens fed 20% and 100% biotin diets. Reovirus infection had no effect on PPD and PHA-P responses. However, in the choline experiment, reovirus-infected chickens had elevated titers. These data indicate that reovirus infection had no adverse effect on the immunocompetence of chickens 8 weeks postinfection. Dietary deficiencies also had no adverse effect on the immunocompetence of 8-week-old reovirus-infected and uninfected chickens.

[Current immunologic aspects of kidney transplantation]

The results of clinical kidney transplantation are mainly dependent on immunologic factors many of which are unknown or of unspecified importance. Blood transfusions have a favorable effect on graft prognosis, although our knowledge about optimal transfusion protocols and transfusion-induced mechanisms is still incomplete. The value of HLA-typing is controversial: whereas compatibility of the "classical" HLA-A,B,C antigens improves graft survival only moderately, HLA-DR typing, routinely performed for the last 3 years only, might be of greater importance. In addition, non-HLA systems, such as endothelial/monocytic antigens or the Lewis blood group system, appear to play a role in graft rejection. The individual immune reactivity a recipient to a large extent determines the fate of a graft. The multifactorial dependence of graft prognosis is discussed in this report.

Host defense systems in cattle exposed to polybrominated biphenyl

In vivo and in vitro immunologic studies were undertaken in 114 Holstein cattle, 60 of which had detectable polybrominated biphenyls (PBB) in adipose tissue. The tissue PBB concentrations were between 0.02 and at least 1,000 mg/kg. An immunologic test profile was used to evaluate the influence of PBB on bovine immune competence. The profile included serum immunoglobulin determinations, autoantibody studies, lymphocyte subpopulation determinations, lymphoblastogenesis assays, delayed hypersensitivity skin testing, and neutrophil function studies. The results of the evaluation indicated that the host defenses are intact, both in quantity and function, in cattle with PBB body burdens ranging from 0.02 and 24.0 mg/kg for at least 2 years. Cattle fed 25 g of PBB daily during the acute toxicity study exhibited usual immune competence until they accumulated 500 g of PBB (tissue concentrations exceeding 1,000 mg/kg). Cattle that were fed more than 500 g of PBB became moribund and exhibited changes in neutrophil function tests and serum antibody titers.

Survival in Hodgkin's disease: the role of immunocompetence and other major risk factors

The prognostic value of age, sex, symptoms, histopathology, lymphocyte count, skin tests, immunocompetence (lymphocyte response profile to a spectrum of PHA concentrations), and stage was evaluated in 35 previously untreated patients with Hodgkin's disease by multiple linear regression and logistic analysis. Immunocompetence exhibited the highest correlation (R = 0.537) with survival status and was required as a common denominator for deriving best sets of two or more variables. In addition, immunocompetence contributed to all other variables combined (p = 0.023), whereas stage did not (p = 0.116). Immunocompetence, age, symptoms, and histopathology generated a highly discriminant (R = 0.784) model not improved by stage or by other variables (p greater than or equal to 0.159). The utility and generalizability of this model are shown by a correct classification of 91.2% of cases according to expected versus actual survival status and by a predicted correlation (R) of 0.71, respectively, neither improved by sex, lymphocyte count, skin tests, or stage. In comparison, the conventional triad of stage, symptoms, and histopathology correctly classified only 70.6% of cases and showed actual and predicted correlations with survival status of R = 0.550 and R = 0.51. We conclude that immunocompetence is a powerful discriminant risk factor in Hodgkin's disease that exerts a pivotal role on survival and serves as a basis for models of greater discriminant power and generalizability than the conventional stage-based evaluation triad. Immunocompetence-based models are expected to provide a more discriminating basis for clinical evaluation, prediction of prognosis, and treatment selection for patients with Hodgkin's disease.

Immunotoxicology in the pharmaceutical industry

Development of an immunotoxicology program within the pharmaceutical industry is described. With few guidelines in the area and a multitude of factors to consider, a basic screen for evaluating immune competence in species routinely used in toxicologic studies has been proposed. The future of immunotoxicology depends upon the ability of the selected immune function tests to be predictive of human risk.

Levamisole: a double blind immunological study

The immunological effects of a 4-week course of levamisole have been assessed by a randomised double blind study of a group of cancer patients judged to have a poor prognosis. No change in immunological status was recorded during a 6 months follow up, using a battery of tests including DNCB response. Mantoux response, lymphocyte count, PHA stimulation and serum immunoglobulin levels. 38% of patients complained of side-effects from the levamisole and 17% stopped the treatment. It is concluded that any beneficial effects of levamisole in patients with advanced cancer may be mediated by a non-immunological mechanism, or by some immunological process other than those studied here, or may require a longer period of administration than 4 weeks. Variation in skin test results in the placebo group throw some doubt on previous reports of immunopotentiation of cancer patients by levamisole.

Adjuvant immunotherapy of carcinoma colli with levamisole. Prevention of immunological depression following surgical therapy and radiotherapy

Of 57 patients with carcinoma colli who underwent radical surgery followed by radiotherapy, 15 were treated with levamisole at a dose level of 150 mg a day for 2 consecutive days, every other week, starting 3 days before surgery. Another 17 patients received levamisole in the same manner except that the administration started simultaneously with post-operative radiotherapy. The immune competence of patients was determined in terms of immune globulin level, DNCB test, PHA skin test and lymphocyte blastogenic response to PHA, and was compared between the levamisole-treated group and the control group. Levamisole had little influence on immune globulin levels and skin reactions to PHA. The DNCB test after levamisole therapy showed no difference in the rate of positive response to DNCB between the levamisole group and the control group. Levamisole, when started before surgery, prevented the postoperative depression of lymphocyte responsiveness to PHA and could more or less enhance the lymphocyte blast formation that had been depressed by radiotherapy.

Difference in the ability of compactin and oxidized cholesterol, both known inhibitors of cholesterol biosynthesis, to suppress in vitro immune responses

Compactin, a fungal metabolite, is a well-characterized competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase, the enzyme which generally controls the rate of cholesterol biosynthesis in mammalian cells. Various products of cholesterol oxidation, e.g., 25-hydroperoxycholesterol and 25-hydroxycholesterol, also inhibit HMG CoA reductase but by an unknown mechanism which operates only in intact cells. In addition, oxidized cholesterol increases cholesterol esterification and suppresses the increase in low-density lipoprotein receptors which is the normal consequence of decreasing low-density lipoprotein supply. There are therefore, three ways in which the availability of nonesterified cholesterol to mammalian cells is decreased by oxidized cholesterol. It has been suggested that potent in vitro immunosuppression by compounds such as 25-hydroxycholesterol in the presence of cholesterol-containing fetal calf serum is a consequence of their ability to suppress cholesterol biosynthesis. This has been disputed in a previous paper (Humphries, G. M. K., and McConnell, H. M., J. Immunol., 122: 121-126, 1979) because mevalonate, the product of HMG CoA reductase activity, fails to abrogate the suppression. The present paper reports that compactin fails to suppress in vitro immune responses at concentrations known to inhibit HMG CoA reductase (either in the isolated or cellular form). This finding supports the previous conclusion that suppression of HMG CoA reductase activity is not sufficient to inhibit in vitro immune responses in the presence of an exogenous source of cholesterol.

Augmentation of the development of immune responses of mice against allogeneic tumor cells after adriamycin treatment

In C57BL/6J mice, depending on the dose of P815 cells used for immunization, Adriamycin exerted different effects on the cell-mediated lytic response and complement-dependent cytotoxicity. At the dose of 3 X 10(7) P815 cells, Adriamycin treatment had no apparent effect on cell-mediated lytic response regardless of timing of drug treatment. At lower doses of antigen (10(7) or 5 X 10(6) cells), the response was augmented in Adriamycin-pretreated mice. Similarly, under conditions which led to a suboptimal complement-dependent humoral response of untreated control, Adriamycin pretreatment resulted in an augmented response; under conditions of maximal response, Adriamycin was suppressive. Suppression was maximal if the drug was injected at either the same time or shortly before or after antigen. The cell-mediated lytic response was proportional to the dose of antigen used, while the complement-dependent humoral lytic response was inversely proportional to dose of antigen in the range used in these experiments. Secondary cell-mediated lytic response in culture was also augmented if mice had been pretreated with Adriamycin 5 days before the primary immunization. The cell-mediated lytic response of spleen and peritoneal exudate cells from mice immunized with relatively low doses of P815 cells 5 days after treatment with Adriamycin was increased 12 to 15 days after immunization. The cytotoxic effects were present in both plastic adherent and nonadherent fractions of either spleen or peritoneal cell populations. All these effector cells were found to be anti-Thy 1.2 sensitive. The phagocytic activity of spleen cells was increased after immunization, but no drug effect was observed; following 24 hr of culture, however, cells from drug-treated immunized donors had increased phagocytic activity as compared to that of controls. Increased phagocytosis also developed in cells nonadherent to plastic.

Indomethacin enhancement of immunocompetence in melanoma patients

Lymphocyte responses to the mitogens concanavalin A (Con A) and phytohemagglutinin (PHA) are important in vitro parameters of immunocompetence in cancer patients. The tempo and intensity of this response is regulated by monocytes. We found that the blood lymphocyte response to one or both of these mitogens was significantly depressed in 32 of 33 melanoma patients compared to 29 normal control subjects. However, these responses were significantly enhanced when the drug indomethacin, a prostaglandin synthetase inhibitor, was added to cultures of peripheral blood mononuclear cells (PBMCs) from the melanoma patients, but not from the normal control subjects. For example, at a 1 microgram/ml dose of Con A, the mean response of melanoma patients increased from 56% to 81% of the normal mean response, whereas at 20 micrograms/ml PHA the mitogen response increased from 57% to 77% of normal when PMBC were incubated with indomethacin (P less than 0.001). Overall, indomethacin enhanced the mitogen responses of melanoma patients by 35% to 85%, whereas indomethacin increased the response in normal subjects by only 5% to 15%. The mitogen response of monocyte-depleted ER+ lymphocytes for melanoma patients was equivalent to that of normal control subjects, and there was no enhancement of this response in the presence of indomethacin. This suggests that the abnormality was due to an altered function of immunoregulatory monocytes. The enhancement by indomethacin in melanoma patients was not significantly influenced by their stage of disease, age, or the proportion of blood monocytes. The decreased levels of cellular immunocompetence in these melanoma patients, as measured by their lymphocyte proliferative responses to mitogens, therefore appears to be associated with an abnormality in monocyte function that is partially corrected by indomethacin.

Studies on T-lymphocyte activation. I. Is competence inductions in thymocytes by phorbol myristate acetate, an accessory cell-independent event?

The effect of phorbol myristate acetate (PMA) on lectin-induced murine thymocyte activation was studied. PMA itself failed to stimulate thymocyte proliferation, but potentiated concanavalin A (Con A)-induced thymocyte activation. A brief incubation of thymocytes with PMA changed the responsiveness of these cells to an optimal mitogenic dose of Con A present during the entire subsequent culture period. Further studies showed that PMA induced in a dose-dependent way within 30 min. an optimal competence of thymocytes to respond to the T-cell growth factor interleukin-2 (IL-2). In contrast to lectin-triggered competence induction, PMA-triggered induction of competence in thymocytes seemed to be independent of accessory cells.

Immunocompetence over the lifespan of mice exposed in utero to carbofuran or diazinon: I. Changes in serum immunoglobulin concentrations

Pregnant F2 dihybrid mice received either a vehicle-control or 1 of 2 doses of the anticholinesterase pesticides Carbofuran (0.01 or 0.50 mg/kg) or Diazinon (0.18 or 9.00 mg/kg) in the diet daily throughout gestation. All mothers gave birth to viable, overtly normal offspring at term. However, a significant number (12%) of pups born to dams who received 9.00 mg/kg Diazinon died prior to weaning on day 28; necropsy findings were consistent with death from respiratory infection. There was no significant difference in mortality between control and pesticide-exposed offspring once they reached 28 days of age. Determinations of 5 different classes of serum immunoglobulin (Ig) concentrations (IgG1,IgG2a,IgG2b, IgA, IgM) at 101, 400 and 800 days of age indicated transient but consistent disturbances of 2 Ig classes in offspring as a result of prenatal pesticide exposure. IgG1 concentrations of male offspring exposed to 0.50 mg/kg Carbofuran or 0.18 mg/kg Diazinon were significantly elevated at 101 days but not at 400 or 800 days of age. IgG1 concentrations of female offspring exposed to 0.01 mg/kg Carbofuran or 9.00 mg/kg Diazinon were significantly depressed at 101 days but not different from controls at 400 or 800 days of age. Changes in IgG2b levels generally were similar to those recorded for IgG1 but of smaller magnitude. There were no significant effects on serum IgG2b or IgM concentrations, and only equivocal effects on IgA, as a consequence of prenatal exposure to either pesticide.

Immunological evaluation of the tumorigenic response to implanted polymers

This short report concentrates on a close look at the immunological status of experimental animals which were implanted with a known dose of tumor and polymer implant. The implanted polymers used represented the most common biocompatible materials employed in current surgery. The immunological studies all were done in vitro on the cellular level. The studies suggested that there is a noticeable change of the immune system when inorganic biocompatible polymers are used in experimental animals.

Host age and H-2 tolerance in chimeric mice: mixed lymphocyte reactivity, cell-mediated lympholysis and responses to hapten-modified self

In order to further our understanding of the reasons for the increased susceptibility of aged animals to autoimmunity, neoplasms and infectious diseases, experiments were performed to determine the ability of an aged environment to induce and support tolerance to major histocompatibility complex (MHC) determinants as well as to support the development of a specific immune response to modified self-determinants. The degree and mechanisms of tolerance to host and donor histocompatibility antigens were studied in bone marrow chimeras of the type (C57B1/6 X CBA)F1 leads to (C57B1/6 X DBA/2)F1 (BCF1 and BDF1, respectively). BCF1 bone marrow donors were 6 weeks old and BDF1 hosts were 18 months old at the time of chimerization. Four to ten months later, chimeras were found to fully tolerant to all three parental haplotyes and competent to respond to fourth-party strains as assessed in both mixed lymphocyte reactions and cell-mediated lympholysis. Tolerance to parental haplotypes could not be attributed to active suppression of reactivity. The aged host environment proved incapable of supporting the development of anti-modified self-reactivity as attested by the fact that neither the senescent BDF1 mice nor the BCF1 leads to BDF1 chimeras established in aged hosts could respond to trinitrophenol-modified autologous parental cells. In contrast, young BDF1 mice and BCF 1 leads to BDF1 chimeras established in young adult hosts were competent to respond to trinitrophenol-modified autologous and parental cells in an MHC restricted fashion. The significance of these results to the susceptibility of aged animals to intracellular parasitic infections and neoplasia is discussed.

Chemoimmunotherapy of disseminated malignant melanoma with DTIC-BCG, transfer factor + melphalan

The experimental synergism of melphalan with DTIC and the ability of transfer factor to improve immunocompetence were the basis of an attempt to improve therapeutic results in disseminated malignant melanoma. Sixty-four evaluable patients with disseminated malignant melanoma were treated in a 21-day cycle as follows: DTIC 250 mg/M2 intravenously days 1 to 5, Connaught BCG 6 X 10(8) organisms on days 7, 12, and 17 by scarification, and transfer factor 1 unit (10(9) lymphocytes equivalent, from immunocompetent relatives of patients) subcutaneously on day 12, with or without L-PAM 30 mg/M2 on day 1. Twenty-nine patients received L-PAM and 35 did not. Remission rates of 17% and 23%, respectively, occurred in these groups. An additional 15 patients received DTIC-BCG and three doses of transfer factor on days 7, 12, and 17 and had a remission rate of 20%. Remission duration and survival were compared to historical controls of 111 patients treated with DTIC and 89 treated with DTIC-BCG. Median survival on DTIC-BCG-Transfer Factor was seven months compared to four months for DTIC (P = .003) but did not differ from DTIC-BCG. Addition of L-PAM did not improve remission duration or survival compared to DTIC-BCG but enhanced myelosuppression and immunosuppression. A 60% increase in delayed type hypersensitivity to recall antigens occurred in this study compared to 34% with DTIC-BCG (P = .005). Prognosis and immunocompetence were not directly related. In summary, in this study, (1) transfer factor therapy did not enhance the clinical effects of DTIC-BCG, although it augmented delayed type hypersensitivity to recall antigens; and (2) L-PAM was not additive to DTIC in the treatment of disseminated malignant melanoma and may have abrogated the effect of immunotherapy.

[Participation of cholinergic mechanisms in the regulation of immunological processes]

Chronic administration of cholinomimetic (arecolin, pilocarpin, nicotin) and cholinolytic (bezohexonium, pedifen) drugs produces changes of different directions in the number of rosette-forming cells in the spleen of CBA mice immunized with sheep red blood cells. The analysis performed does not allow the effect of the drugs on immunologic processes to be accounted for by an immediate action on lymphoid cells or by an action of the function of the pituitary-adrenal system.

[Effect of BCNU on the kinetics of the primary immune response in mice]

It was shown in experiments on mice administered the alkylating agent BCNU (1,3-bis/2-chlorethyl/-I-nitrosourea) at a dose of 20 mg/kg 48 or 72 hours following immunization wtih sheep red cells that kinetics of producing antibody-forming cells assumes a wave-like pattern with a sharp alternation of rises and falls in the number of antibody inducers. Analysis of the data obtained allowed a conclusion that BCNU does not affect the recruitment -- transformation of the precursor cells to antibody-forming cells.

[The immune competence of patients with Crohn's disease (author's transl)]

The cell-mediated and humoral immune responses were assessed in 15 patients with Crohn's disease and in 28 age-matched control subjects by means of several in vivo and in vitro methods. The disease activity in most patients was absent or moderate. Studying cellular immunocompetence we investigated the skin reactivity to various recall antigens (Candida, Trichophytin, Mumpsantigen, Streptokinase-Streptodornase, PPD), the primary immune response to Dinitrochlorobenzene (DNCB) and Keyhole Limpet Hemocyanin (KLH), and the lymphocyte transformation induced by mitogens (Phytohemagglutinin, Concanavaline A, Pokeweed Mitogen) and specific antigens. Humoral immunity was studied by measuring immunoglobulins, isohemagglutinins, and the antibody response to KLH. In addition, complement components and (in 10 patients) the proportions of T- and B-lymphocytes in the peripheral blood were evaluated. Cutaneous responsiveness to Candida, Mumps-antigen, SK-SD, and DNCB as well as the cellular immune response to KLH were impaired in patients with Crohn's disease (significance was reached for SK-SD, DNCB, and the mean area of induration). The lymphocyte transformation test with PHA, ConA, and PWM revealed normal results. For specific antigens (PPD, SK-SD, KLH) a good correlation could be demonstrated between delayed hypersensitivity and the in vitro lymphocyte responsiveness. Humoral immunity was not unequivocally impaired in Crohn's disease. Five patients with Crohn's disease proved constantly decreased total absolute lymphocyte counts in peripheral blood. The proportions of T- and B-lymphocytes and the complement-levels were corresponding to those in normal controls. No correlation was found between immunological and clinical parameters. In conclusion, patients with Crohn's disease exhibited a partial impairment of the cellular immune response, whereas humoral immunity was not affected. However, it remains to be elucidated whether this immune defect represents a basic pathogenetic factor in the onset of the disease.

An in vivo model for assessing effects of drugs and toxicants on immunocompetence

An in vivo assessment of the capacity of exposed animals to respond to antigenic challenge is recommended as the first screening phase for detecting potential immunotoxicants, with subsequent in vitro functional tests utilized to pinpoint the site of induced cellular alteration. Risk assessment of a candidate toxicant is based on a comparison of immune profiles of exposed animals with those of animals treated with prototype immunotoxicants. Extrapolation to man is facilitated by the use of licensed vaccines for antigenic challenge and the selection of clinically useful pharmaceutical drugs as prototype immunotoxicants. Three chemically induced alterations in immune responses are presented: 1) Immunosuppression characterized by impaired capacity to produce IgG and IgM classes of antibody on stimulation, 2) chronic high levels of IgE antibody in response to commonly encountered antigens, 3) modification of the capacity to mount an inflammatory response to antigenic material.