Recent developments in immunomodulatory therapy

Immunomodulatory properties of new conjugates of muramyl dipeptide and nor-muramyl dipeptide with retro-tuftsin (Arg-Pro-Lys-Thr-OMe)

Six new conjugates of muramyl dipeptide and nor-muramyl dipeptide with retro-tuftsin were synthesised at Gdansk University of Technology. All compounds were investigated at Medical University of Gdansk. Their immunomodulatory properties were assessed using in vitro cultures of human subpopulations of white blood cells (peripheral blood mononuclear cells, peripheral blood lymphocytes, monocytes). We examined the viability of blood cells incubated with examined conjugates, as well as their ability to stimulate secretion of cytokines (TNFalpha--tumour necrosis factor alpha, IL6--interleukin 6) and cytotoxic activity of NK (Natural Killer) cells. Complementation in biological activity of muramyl dipeptide (MDP) and tuftsin in conjugates proved to be beneficial in the field of immunoadjuvanticity. Our investigations proved that new conjugates acquired features that native immunomodulators did not reveal separately. In examined compound, the part responsible for inducing cytotoxic activity of NK cells was the tuftsin part of the conjugates. MDP in conjugates was responsible for compound-induced synthesis of TNFalpha. The results of our study imply usefulness of the examine compounds (mainly A and B), as potential therapeutic agents.

Requirement for TLR9 in the Immunomodulatory Activity ofPropionibacterium acnes

Propionibacterium acnes (formerly Corynebacterium parvum) is part of the human flora and, as such, is associated with several human pathologies. It possesses strong immunomodulatory activities, which makes this bacterium interesting for prophylactic and therapeutic vaccination. The bacterial component(s) and the host receptor(s) involved in the induction of these activities are poorly understood. We show in this study that TLR9 is crucial in generating the characteristic effects of killed P. acnes priming in the spleen, such as extramedullary hemopoiesis and organ enlargement, and granuloma formation in the liver. Furthermore, the ability to overproduce TNF-alpha and IFN-gamma in response to LPS, lipid A, synthetic lipopeptide Pam(3)CysK(4), or whole killed bacteria was present in P. acnes-primed wild-type, but not TLR9(-/-), mice. Finally, P. acnes priming failed to induce enhanced resistance to murine typhoid fever in TLR9(-/-) mice. Thus, TLR9 plays an essential role in the induction of immunomodulatory effects by P. acnes. Because IFN-gamma is a key mediator of these effects, and enhanced IFN-gamma mRNA expression was absent in spleen and liver of P. acnes-primed TLR9(-/-) mice, we conclude that TLR9 is required for the induction of IFN-gamma by P. acnes.

Enhancement of natural and acquired immunity by Lactobacillus rhamnosus (HN001), Lactobacillus acidophilus (HN017) and Bifidobacterium lactis (HN019)

Consumption of lactic acid bacteria (LAB) has been suggested to confer a range of health benefits including stimulation of the immune system and increased resistance to malignancy and infectious illness. In the present study, the effects of feeding Lactobacillus rhamnosus (HN001, DR20), Lactobacillus acidophilus (HN017) and Bifidobacterium lactis (HN019, DR10) on in vivo and in vitro indices of natural and acquired immunity in healthy mice were examined. Mice were fed daily with L. rhamnosus, L. acidophilus or B. lactis (10(9) colony forming units) and their immune function was assessed on day 10 or day 28. Supplementation with L. rhamnosus, L. acidophilus or B. lactis resulted in a significant increase in the phagocytic activity of peripheral blood leucocytes and peritoneal macrophages compared with the control mice. The proliferative responses of spleen cells to concanavalin A (a T-cell mitogen) and lipopolysaccharide (a B-cell mitogen) were also significantly enhanced in mice given different LAB. Spleen cells from mice given L. rhamnosus, L. acidophilus or B. lactis also produced significantly higher amounts of interferon-gamma in response to stimulation with concanavalin A than cells from the control mice. LAB feeding had no significant effect on interleukin-4 production by spleen cells or on the percentages of CD4+, CD8+ and CD40+ cells in the blood. The serum antibody responses to orally and systemically administered antigens were also significantly enhanced by supplementation with L. rhamnosus, L. acidophilus or B. lactis. Together, these results suggest that supplementation of the diet with L. rhamnosus (HN001), L. acidophilus (HN017) or B. lactis (HN019) is able to enhance several indices of natural and acquired immunity in healthy mice.

Effect of transfer factor on myelosuppression and related morbidity induced by chemotherapy in acute leukaemias

The aim of this study is to determine the safety and efficacy of Transfer Factor (TF) in accelerating the haematopoietic recovery in patients with acute leukaemias (AL), following intensive therapy to induce remission of the disease. Twenty-two patients with different types of AL (16 AML, three BC-CML and three ALL) were studied. The patients were divided in two groups. Group 1 (eight AML, two BC-CML and one ALL) received, after myelosuppression induced by chemotherapy, TF (1 unit daily, subcutaneous) until leucocyte count was > 2.5 x 10(9)/l and platelet count > 80 x 10(9)/l. Group 2 was considered the control group and did not receive TF. Treatment with TF accelerated the recovery of neutrophils, leucocytes, platelets (P < 0.001) and haemoglobin (P < 0.01). As a logical consequence, incidence and severity of infection and haemorrhage were lesser in the TF group than in the control group. There was no evidence that TF accelerated the re-growth of leukaemic cells. It seems that TF is safe in AL, accelerating haematopoietic recovery. However, it should be used with caution until results of additional trials become available.

Adjuvant properties of propionibacterium avidum KP-40 in vaccination against endemic viral and bacterial infections. I. Swine immunized with live attenuated Aujeszky's disease virus vaccine and experimentally infected with virulent viruses

Forty 5-month old swine were treated with immunomodulating Propionibacterium avidum KP-40 (PA) and/or immunized with live attenuated Aujeszky's disease (AD) virus vaccine (SuivacA); 8 weeks later all animals were infected with virulent AD viruses (NIA-3). Seven of 10 swine vaccinated without PA developed mild/moderate symptoms of infection with 3- to 5-day fever and a temporary halt in weight gain. Application of PA together with the vaccine lowered the morbidity rate, shortened the period of fever and speeded recovery. Only low levels of virus-neutralizing IgG antibodies were found in vaccinated swine and application of PA did not influence antibody titers.

Perturbation of metabolism and disposition of cyclophosphamide by interferon and poly I:C, an interferon inducer, in mice

The effects of interferon and poly I:C on the metabolism and disposition of cyclophosphamide were investigated in mice. Elimination of cyclophosphamide from the blood was decreased in mice treated 24 hr previously with interferon (2.5 x 10(6) U/kg, intraperitoneally) or poly I:C (10 mg/kg, intraperitoneally). The blood half-life of cyclophosphamide in interferon or poly I:C-pretreated mice was prolonged to a first order of disappearance of 29.3 and 41.6 min., respectively, compared to 19.0 min. in control mice. Also, the rate of formation of activated cyclophosphamide was delayed and the peak blood level of activated cyclophosphamide was not as high in poly I:C-pretreated and interferon-pretreated mice as in control mice. The decreased elimination and elevated blood levels of activated cyclophosphamide were reflected by changes in its antitumour activity and toxicity in the mice. In 9,000 x g supernatants prepared from the liver homogenate of mice treated with interferon or poly I:C, the oxidation of cyclophosphamide in vitro has decreased by 29 and 37%, respectively. However, the addition of these agents to normal 9,000 x g supernatant suspensions had no effect on cyclophosphamide oxidation. Modulation of the metabolism and disposition resulted from depressed levels of cytochrome P-450 in the hepatic microsomes of the mice administered interferon or poly I:C.

Immune stimulation. A new approach in the treatment of glomerulonephritis

We discuss here a new approach to the treatment of idiopathic membranous glomerulonephritis (IMGN). Steroids and cytotoxic drugs have been used during the last years for the treatment of this disease, but the results are controversial. We develop here the hypothesis that the pathogenesis of IMGN is a relative incompetence of the immune system in clearing foreign antigens. Therefore, most patients should benefit from immune stimulation in the direction of a greater and more avid immune response.

Autolymphocyte therapy

Autolymphocyte therapy is medical treatment based upon the infusion of autologous lymphocytes that have been immunized or modulated in vitro. These infused cells subsequently provoke fundamental immunobiologic changes in the host. We suggest that autolymphocyte therapy might be a useful approach in the treatment and prophylaxis of several diseases.

Update and future perspectives of a thymic biological response modifier (Thymomodulin)

Thymomodulin (Ellem Industria Farmaceutica spa, Milan, Italy) is a calf thymus acid lysate with immunomodulating activities. It is composed of several peptides with a molecular weight range of 1-10kD. Extensive studies in animal systems showed that Thymomodulin exhibited no, or very little toxicity even when used at high doses. Studies done in vitro and in vivo demonstrated that Thymomodulin is a biologically active compound which regulates the maturation of human and murine pre T lymphocytes, as well as modulate the functions of apparently mature human and animal B and T lymphocytes. It was observed that Thymomodulin can promote myelopoiesis as demonstrated by an increase of granulocyte-macrophage colonies in agar. Although additional studies to examine its target cell lineage are required, it appears that Thymomodulin exhibits specificity toward T cells. Therefore, enhancement of other cell lineage functions by Thymomodulin may be indirect, and mainly due to its effect on T cells. Of major importance is to note that Thymomodulin is prepared in a manner which allows it to maintain its biological activity when administered orally.

Biological response modifiers in the management of viral infection

The rapid evolution of immunopharmacology as a recognized scientific discipline dedicated to unraveling complex interrelationships between immunologic responsiveness and disease states in general supports the importance of the potential role biological response modifiers have in clinical medicine. To administer a drug, or combination of drugs, that safely, effectively, and favorably alter the course of infection, cancer, autoimmune disease, and allergy is within grasp. Although the greatest emphasis on therapeutic application of BRMs is placed on cancer, many of these immunomodulating agents have well-documented effects on the course of infectious disease. By either restoring immune responses or by enhancing the response of a normal immune system, it is conceivable that BRM therapy will someday be used routinely as adjunct therapy in the management of viral infections in companion animals.

Immunomodulating activity of Wy-41,770 (5H-dibenzo[A,D]cyclohepten-5-ylidene) acetic acid

The immunomodulatory effects of Wy-41,770 (5H-dibenzo[a,d]cyclohepten-5-ylidene) acetic acid, were compared to levamisole and indomethacin in several in vivo models. In the Jerne plaque assay, Wy-41,770 (1 and 100 mg/kg, p.o.) administered on day 1 after sensitization suppressed IgM plaque forming cells (PFC) while levamisole was active when given on days 1 and 2 after sensitization. In contrast, indomethacin administered on days 2 and 3 after sensitization increased PFC. In the rat experimental allergic encephalomyelitis (EAE) model, Wy-41,770 reduced limb paralysis at 10 and 100 mg/kg, p.o. when dosed before sensitization. Indomethacin was active too when predosed in the rat EAE model. In the methylated bovine serum albumin model (MBSA) delayed hypersensitivity (DH) model in mouse, Wy-41,770 (10 mg/kg, p.o.) given on day 1 prior to sensitization and day 2 after sensitization in subliminally sensitized animals augmented the DH response while inhibiting the subliminal DH response when administered at 6 hr after challenge. Levamisole showed similar activity in this subliminal model while indomethacin given 6 hr post challenge was inhibitory. All three drugs were inactive in mice normally sensitized to MBSA at the same drug regimens. In guinea pigs, subliminally sensitized to tuberculin, Wy-41,770 (10 and 100 mg/kg, p.o.) and levamisole augmented the DH response. No changes in DH response were observed for both drugs in normally sensitized guinea pigs. In the rat adjuvant arthritic model, Wy-41,770 (5 and 15 mg/kg, p.o.) inhibited day 16 uninjected paw edema and restored significantly the depressed proliferative responses to mitogen by spleen cells taken from the same arthritic rats at day 16. The moderate immunomodulatory activity of Wy-41,770 may contribute along with its antiinflammatory activity, towards the treatment of arthritic diseases.