William H. Stimson

Sex Hormones and Immune Function

Publisher Summary This chapter discusses the role of sex hormones in immune function. Testosterone can increase susceptibility to infection and depress the reactivity of passively transferred lymphocytes. It may also inhibit development of autoallergic thyroiditis in male rats and reduce the severity and occurrence of adjuvant arthritis. Thymic atrophy occurs at puberty in both sexes. In an earlier study described in the chapter, thymic lymphocytes remaining after treatment were found to be more responsive to concanavalin A and phytohemagglutinin stimulation. Estrogens can be shown to generally depress cell-mediated immunity but can elevate antibody responses to T-dependent antigens. In another study, long-term treatment with the synthetic estrogen diethylstilbestrol depressed mitogen responsiveness in female mice and caused a peripheral lymphopenia. Natural killer cell activity was also reduced by estrogen. Prostate cancer patients receiving estrogen as a direct antitumor treatment may be compromised immunologically by this measure. There is some evidence that cancer immunosurveillance and also the ability to combat infection may be depressed in this way. There is compelling evidence to suggest that the sex steroids do have the capacity to influence the immune response in adults and are also important in the maturation of the immune system during fetal life.

In Vitro Susceptibilities of Shigella flexneri and Streptococcus pyogenes to Inner Gel of Aloe barbadensis Miller

ABSTRACT Aloe barbadensis Miller (or Aloe vera) has widespread use in health products, and despite numerous reports on the whole plant, little work has been performed on the inner gel, which has been used extensively in these products. This report describes the in vitro susceptibilities of two bacteria to this component.

CORRELATION OF THE BLOOD-LEVEL OF A PREGNANCY-ASSOCIATED α-MACROGLOBULIN WITH THE CLINICAL COURSE OF CANCER PATIENTS

The variations in serum level of a pregnancy-associated alpha-macroglobulin (P.A.M.) were studied during the treatment of breast-cancer patients. Good correlation was found between P.A.M. concentrations and the course of the disease--levels rose prior to the clinical recognition of metastatic disease and decreased significantly on successful treatment. Periodic P.A.M. determinations may allow detection of tumour recurrence while it is still at a treatable stage.

Immunoneutralisation of GnRH-I, without cross-reactivity to GnRH-II, in the development of a highly specific anti-fertility vaccine for clinical and veterinary use ☆

In recent years, several forms of gonadotrophin releasing hormone (GnRH) molecules have been isolated from primate brain. These molecules are very similar in sequence and this raises the question of whether previously developed neutralisation vaccines based on GnRH (now termed GnRH-I) would remove other forms of GnRH (namely GnRH-II) as well. As the function of these other molecules has not yet been clearly defined, potential health risks could exist by their ablation. In view of the high sequence homology between the molecules, this paper describes the production of highly specific polyclonal antibodies against GnRH-I and GnRH-II, with negligible cross-reactivity. The ultimate aim of this is to develop an anti-fertility vaccine which does not present any inappropriate side-effects, caused by neutralisation of a GnRH molecule which may or may not be directly involved in reproduction. Several formulations were investigated, based on analogues of the following molecules, conjugated to tetanus toxoid: 1. GnRH-I pGlu-His-Trp-Ser-Try-Gly-Leu-Arg-Pro-Gly-NH2 and 2. GnRH-II pGlu-His-Trp-Ser-His-Gly-Trp-Tyr-Pro-Gly-NH2. The specificity of the antibodies produced was examined, together with effects on fertility and any inappropriate side-effects. Immunostaining of hypothalamic sections was carried out, using the generated antisera, to determine the regional distribution of GnRH-I and GnRH-II neurones, as well as to further evaluate the specificity of the antibodies.

Immunoneutralisation of gonadotrophin releasing hormone : a potential treatment for oestrogen-dependent breast cancer

The aim of this study was to assess the therapeutic potential of active immunisation with GnRH-glycys-PPD in a hormone-dependent experimental model. Mammary tumours were induced in female rats using dimethylbenzanthracene (DMBA) and the effects of GnRH immunoneutralisation on tumour development were evaluated. High titres of anti-GnRH IgG correlated with a decrease in oestrogen levels and subsequent tumour suppression. A comparison of immunised and non-immunised animals showed that when GnRH-specific IgG levels were at a maximum titre (80-100 micrograms/ml), nearly 10% of the GnRH-glycys-PPD treated animals showed mammary masses, compared with all the non-treated animals at the same stage in the study. When the antibody levels fell, tumour regrowth was observed, but to a level below that observed in the non-treated animals. Following further treatment with the analogue, the tumours regressed again, showing their retention of hormone dependency. This is consistent with other endocrine manipulations in the treatment of breast cancer; the advantages of immunisation with GnRH-glycys lies in its non-toxicity and reduction in side-effects, which were mainly adjuvant-induced.

Influence of carrier protein conjugation site and terminal modification of a GnRH-I peptide sequence in the development of a highly specific anti-fertility vaccine part I

PROBLEM: We previously immunoneutralized gonadotrophin releasing hormone (GnRH), using an analogue of GnRH (des‐1 GnRH‐I), conjugated to tetanus toxoid via a carbodiimide reaction. The castration effect on the reproductive system was not consistent in all the treated animals. Therefore, we examined the possibility that conjugation to the carrier protein via the N‐ or C‐terminal could have an effect on efficacy.

Accurate determination of adjuvant-associated protein or peptide by ninhydrin assay.

Modern peptide and subunit vaccines are increasingly having to rely on the use of immunological adjuvants to achieve effective immunity. However, the only adjuvant currently approved for use in humans is aluminium hydroxide, although many adjuvants are currently under preclinical development. Determining immunogen concentration in the presence of adjuvants such as aluminium hydroxide gel, liposomes or NISV has proved to be problematic. One approach has been to use radiolabelled antigens to extrapolate concentration to a preparation using native immunogen. However, the use of a colorimetric assay would allow greater flexibility in terms of immunogen used and would reduce costs and remove safety problems. Of the colorimetric methods we have examined thus far, only the manual ninhydrin assay has produced consistent results with detection of microgram quantities of protein or peptide in the presence of NISV or Alhydrogel, but not liposomes. As the assay relies on the detection of free amino groups after protein hydrolysis, peptides as well as proteins may be effectively determined irrespective of amino acid composition, a considerable advantage over other colorimetric assay systems.

Use of a highly specific monoclonal antibody against the central variable amino acid sequence of mammalian gonadotropin releasing hormone to evaluate GnRH-I tissue distribution compared with GnRH-I binding sites in adult male rats.

PROBLEM:  Recent evidence shows the existence of numerous isoforms of gonadotropin releasing hormone (GnRH), with high sequence homology and a core variable region. This raises the issue that previous GnRH distribution studies may have identified a variety of isoforms. This investigation was carried out to confirm the distribution and binding activity of GnRH‐I only.

Fertility-Disrupting Potential of Synthetic Peptides Derived from the β-Subunit of Follicle-Stimulating Hormone

PROBLEM: Hormone immunoneutralization is hampered by immunologic cross‐reactivity caused by close‐sequence homology between related molecules. One solution is to use smaller fragments to induce antibodies of greater specificity.

Detection of mammary micrometastases by pregnancy-associated α2-glycoprotein (PAG, α2-PAG or PAM) and carcinoembryonic antigen (CEA)

Abstract Eleven of 30, stages 1 or 2 mammary cancer bearers developed conventionally detectable metastases within 8–37 (median, 21)months. Serum PAM rose by >75% above baselines before detection of metastases in all but one of these patients and in 5 of the 19 remaining well. The means of the maximum percentage rises in PAM were 421.9 for the metastatic and 59.9 for the well patients ( P 75% above baseline but fell before metastases appeared), and 10 of the 19 clinically well patients had rises exceeding 75%. This was not bettered by taking a 45% rise in CEA as the discriminant or by using a function of the combined rises in PAM and CEA. Also there were no significant correlations between the absolute values of serum PAM and CEA nor between their incremental changes. Thus PAM rises often detect micrometastases with growth potential in mammary cancer bearers. Whilst CEA rises are only occasionally helpful.