Immunologic regulation of fetal-maternal balance

In vitro evaluation of graft-versus-graft alloreactivity as a tool to identify the predominant cord blood unit before double cord blood transplantation

The transplantation of two cord blood (CB) units obtained from unrelated donors (double CBT) is an effective strategy for adult patients with hematologic malignancies. Sustained hematopoiesis after double CBT is usually derived from a single donor, and only a few transplantation recipients displaying a stable mixed donor-donor chimerism have been reported. We investigated the mechanisms underlying single-donor predominance in double CBT by studying in vitro the role of the graft-versus-graft cell-mediated immune effect in two-way mixed-lymphocyte culture, along with the contribution of differential hematopoietic progenitor (HP) potency in HP mixed cultures. Results for the two-way mixed-lymphocyte culture showed that despite the weak and variable alloantigen-specific cytotoxic potential displayed by CB mononuclear cells, an immune-mediated dominance for one of the two CB units was detected in the majority of experiments. Alloantigen-induced cytotoxic activity was directed toward both CB-HP and phytohemagglutinin (PHA)-activated T lymphoblastoid cells. The CB unit with the higher fold expansion of CD34(+) cells in single-expansion culture was prevalent in the HP mixed-expansion culture, as shown by DNA chimerism evaluation. Based on these data, we hypothesize that the dominant CB unit is able to develop prevalent cytotoxic activity toward activated lymphocytes of the other CB unit, thereby preventing them from exerting alloantigen-specific cytotoxic potential against both activated lymphocytes and HPs of the dominant unit. In accordance with this hypothesis, we propose the evaluation of alloantigen-induced cytotoxic activity generated in two-way mixed-lymphocyte culture and directed toward PHA-activated T lymphoblastoid cells as a tool to identify the potentially predominant CB unit before double CBT.

Unrelated donor umbilical cord blood transplantation versus unrelated donor bone marrow transplantation in adult and pediatric patients: A meta-analysis

The effect of unrelated donor bone marrow transplantation (UBMT) and unrelated donor cord blood transplantation (UCBT) on the outcome of patients with hematological diseases remains controversial. We conducted a meta-analysis using data from controlled clinical trials comparing UCBT to UBMT in patients undergoing hematopoietic stem cell transplantation. Pooled comparisons of studies of UCBT and UBMT in children found that the incidence of chronic graft-versus-host disease (GVHD) was lower with UCBT (relative risk [RR]=0.41; 95% confidence interval [CI] (0.25, 0.68)), and the incidence of grades II-IV aGVHD was also significantly different (RR=0.69; 95% CI (0.55, 0.86)). The incidence of relapse was also lower with UCBT (RR=0.72; 95% CI (0.59, 0.87)). There was no difference in OS in children when studies were pooled (Hazard ratio [HR]=1.25; 95% CI (0.87, 1.78)). For adults, OS (HR=1.26; 95% CI (1.13, 1.40)) was statistically different. Thus, UCBT led to inferior outcomes than UBMT in adults.

Villitis of unknown etiology: noninfectious chronic villitis in the placenta

Villitis of unknown etiology (VUE) is an important pattern of placental injury occurring predominantly in term placentas. Although overlapping with infectious villitis, its clinical and histologic characteristics are distinct. It is a common lesion, affecting 5% to 15% of all placentas. When low-grade lesions affecting less than 10 villi per focus are excluded, VUE is an important cause of intrauterine growth restriction and recurrent reproductive loss. Involvement of large fetal vessels in the placenta (obliterative fetal vasculopathy) in cases of VUE is a strong risk factor for neonatal encephalopathy and cerebral palsy. Although the etiology of the eliciting antigen is unknown, many other characteristics of the immune response have been clarified. VUE is caused by maternal T lymphocytes, predominantly CD8-positive, that inappropriately gain access to the villous stroma. Fetal antigen-presenting cells (Hofbauer cells) expand and are induced to express class II major histocompatibility complex molecules. Maternal monocyte-macrophages in the perivillous space likely amplify the immune response. Although much speculation exists that VUE represents a host-versus-graft reaction analogous to transplant rejection, other eliciting antigens have not been excluded. Irrespective of target antigen or antigens, the pathophysiologic implications of having activated maternal lymphocytes within vascularized fetal tissues are not trivial.

T lymphocytes of recipient origin may contribute to the recovery of specific immune response toward viruses and fungi in children undergoing cord blood transplantation

Patients undergoing allogeneic cord blood transplantation (CBT) benefit from a low risk of graft-versus-host disease (GVHD), but there are still concerns that they be able to recover an effective immune capacity early after transplantation. We investigated the ability to develop in vitro T-lymphocyte-mediated immune response toward human cytomegalovirus and Candida albicans antigens, early and late after transplantation, in children given cord blood transplants from either an HLA-identical sibling or an unrelated donor. Proliferative capacity and frequency of antigen-specific T cells were evaluated; antigen-specific CD4(+) T-cell clones were also generated and characterized for T-cell receptor repertoire diversity, cytokine phenotype, and their origin (either from donor or patient). We found that the majority of recipients can develop a specific response to viral or fungal antigens already early after transplantation. Antigen-specific T-cell clones of both donor and recipient origin contributed to the reconstitution of immune response. Antigen-specific T lymphocytes of recipient origin were detected in patients receiving a transplant from a relative, after a chemotherapy-based conditioning regimen, and who did not have GVHD. Our results document, at a clonal level, that after CBT recovery of either polyclonal or pauciclonal T-cell response toward widespread pathogens is prompt, with some patients benefiting from a contribution of recipient-derived cells.

Implication of maternal-cell contamination in the clinical banking of umbilical cord blood

BACKGROUND

The increasing utilization of human UC blood (UCB) in transplantation has drawn attention to the need for rationalization of selection, collection, processing, testing, banking and release of UCB. However, the issue of maternal blood contamination has not been well addressed. There are concerns that maternal T cells might elicit GvHD post-UCB transplant.

METHODS

Maternal T cells in 58 male UCB allografts were enumerated using fluorescent in situ hybridization and flow cytometry. Obstetric factors, preceding labor, multi-parity and gestational age, were also analyzed.

RESULTS

Levels of maternal cells of 0.75-5.25% were found in 15.5% (9/58) UCB. There was no association of maternal-cell contamination with preceding labor [25% (2/8) with previous delivery versus 35.4% (17/48) first born, P = 0.702], nor any correlation with multi-parity [37.5% (3/8) para > or = 3 versus 16.7% (8/48) para < 3, P = 0.181]. Gestation age of newborns also exhibited no association with maternal-cell contamination (39.47 weeks in newborn UCB with maternal cells, versus 39.58 weeks without: P = 0.674). The extrapolated maternal T cells/kg in nine UCB transplants were 1.05 x 10(5) +/- 1.12 x 10(5) (3.40 x 10(4) - 3.18 x 10(5)).

DISCUSSION

In relation to the arbitrary threshold of 1 x 10(5) T cells/kg in HLA-mismatched transplants utilizing T-cell depleted BM, 22.2% (2/9) of UCB transplants having maternal-cell contamination might be at risk of GvHD. Data support the need for testing for maternal blood in UCB, and evaluating the clinical relevance of GvHD in patients post-UCB transplant. The establishment of guidelines and standards for release of such UCB collections would be advisable in evidence-based UCB transplantation.

Involvement of central, but not placental corticotropin releasing hormone (CRH) in heat stress induced immunosuppression during pregnancy

To clarify whether corticotropin releasing hormone (CRH) and beta-endorphin (betaEP) system mediate maternal immunosuppression in pregnant rats exposed to heat through central or placental pathway, we examined the effects of intravenous (iv) (100 or 500 microg) or intracerebroventricular (icv) (5 microg) administration of CRH receptor antagonist alpha-helical CRH (9-41) on splenic natural killer cell activity (NKCA) as well as betaEP in blood, pituitary lobes, and placenta in pregnant rats at 15 to 16 days gestation. Two-way ANOVA revealed that heat reduced NKCA and elevated blood and pituitary betaEP but did not change placental betaEP. Iv administered 500 microg and icv administered alpha-helical CRH reversed the reduced NKCA and the elevated pituitary betaEP, while iv administration of 100 microg alpha-helical CRH did not. The increased blood betaEP was reversed by iv 100 and 500 microg alpha-helical CRH and icv administration. Both iv and icv administrations reduced placental betaEP independent of heat exposure. Thus, the response of placental betaEP to iv administration of alpha-helical CRH seemed to be stronger than that of pituitary betaEP. These results indicate that alpha-helical CRH which acts on pituitary betaEP antagonizes heat-induced immunosuppression during pregnancy, suggesting that immunosuppression produced by heat stress during pregnancy is mediated by the central CRH system. The placental CRH-betaEP system seems unlikely to be involved in the immunosuppression. Physiologic roles of placental CRH and opioid system should be clarified by future in vitro experiments using placenta specimen including placental immunocyte.

Analysis of immune reconstitution in children undergoing cord blood transplantation

OBJECTIVE

The aim of this study was to investigate and compare immune reconstitution in allogeneic cord blood transplantation (CBT) and bone marrow transplantation (BMT) recipients.

MATERIALS AND METHODS

Twenty-three children underwent CBT from either human leukocyte antigen-identical siblings (11 cases) or unrelated donors (12 cases) were enrolled in the study, together with 23 matched children receiving BMT. Patients were analyzed 2-3 and 12-15 months after transplant. Recovery of T-, B-, and NK-lymphocyte subsets, proliferative in vitro response to mitogens, as well as cytotoxic activities, were investigated.

RESULTS

CBT recipients showed a marked increase in the number of B lymphocytes as compared with patients who underwent BMT (p < 0.001). The absolute number of CD3(+) and CD8(+) T cells, as well as the proliferative response to T-cell mitogens, recovered with time after transplantation, irrespective of the source of stem cells used. Recipients of unrelated CBT had a better recovery of CD4(+) T lymphocytes (p < 0.01). Among patients experiencing acute graft-versus-host disease (GVHD), children given CBT had a much greater production of CD4(+) CD45RA(+) T cells than BMT recipients (p < 0.005). Recovery of NK cell number and innate cytotoxic activities was fast, irrespective of the source of stem cells used.

CONCLUSIONS

Despite the much lower number of lymphocytes transferred with the graft, recovery of lymphocyte number and function toward normal in CBT recipients was rapid and comparable to that observed after transplantation of bone marrow progenitors. This prompt immune recovery possibly was favored by the reduced incidence and severity of GVHD observed in children who underwent CBT.

Pregnancy, HLA allogeneic challenge, and implications for AIDS etiology

Because of the large HLA genetic polymorphism, a human fetus usually has several paternal HLA antigens allogeneic to its mother. The maternal gamma-immunoglobulin (IgG) antibody response to fetal HLA alloantigens is noncytotoxic and associated with local suppression of maternal cell-mediated immunity (CMI) at the maternal-fetal interface. When mother and fetus are syngeneic for most HLA antigens, an increased risk exists for a maternal anti-placental cytotoxic CMI responses, compromising fetal survival. Local suppression of maternal CMI by an anti-HLA IgG response may have evolved to protect the fetoplacental unit from a maternal CMI cytotoxic reaction against expressed developmental neoantigens. A negative aspect of this adaptive response is that infectious organisms bearing HLA-homologous alloantigens (e.g. human immunodeficiency virus type 1, HIV-1) may generate a systemic IgG response suppressing CMI. Findings are reviewed suggesting this is an etiologic factor in the acquired immune deficiency syndrome (AIDS).

Natural killer cell activity reduced by microwave exposure during pregnancy is mediated by opioid systems

We have previously demonstrated immunosuppression including reduced splenic natural killer cell activity (NKCA) in pregnant rats exposed to microwaves produced mainly by their thermal action. To examine the involvement of opioid systems in reduced NKCA in pregnant rats exposed to microwaves at a relatively low level (2 mW/cm2 incident power density at 2450 MHz for 90 min), we assayed beta-endorphin (betaEP) in blood, pituitary lobes, and placenta as well as splenic NKCA in virgin and/or pregnant rats. Although microwaves elevated colonic temperatures by 0.8 degreesC for virgin and 0.9 degreesC for pregnant rats, and betaEP in blood and anterior pituitary lobes (AP) significantly, it did not change blood corticosterone as an index of hypothalamic-pituitary adrenal axis. There were significant interactions between pregnancy and microwave exposure on splenic NKCA, betaEP in both blood and AP, and blood progesterone. Intra-peritoneal administration of opioid receptor antagonist naloxone prior to microwave exposure increased NKCA, blood, and placental betaEP in pregnant rats. Alterations in splenic NKCA, betaEP and progesterone in pregnant rats exposed to microwaves may be due to both thermal and nonthermal actions. These results suggest that NKCA reduced by microwaves during pregnancy is mediated by the pituitary opioid system.

Central administration of interleukin-1 beta reduces natural killer cell activity in non-pregnant rats, but not in pregnant rats

To examine responses of natural killer cell activity (NKCA) to interleukin-1 beta (IL-1 beta) during pregnancy, we determined splenic NKCA as well as blood and brain indicators in virgin and pregnant rats (14 or 21 days gestation) with intracerebroventricular (i.c.v.) administration of IL-1 beta. NKCA was reduced and blood beta-endorphin (beta EP) was increased with the progress of pregnancy. I.c.v. administration of IL-1 beta reduced NKCA and corticotropin-releasing hormone (CRH) in the median eminence (ME), and increased beta EP in virgin rats, but did not change any parameters in pregnant rats with 21 days gestation. These data suggest that the immunosuppressive effect of central administration of IL-1 beta is blocked by pregnancy. CRH in the ME and opioid system seem to be involved in the inhibitory effect of pregnancy on IL-1 beta-induced immunosuppression.

Opioid peptides mediate heat stress-induced immunosuppression during pregnancy

To clarify the involvement of the opioid system in enhanced immunosuppression induced by heat stress during pregnancy, we examined the effects of heat exposure and intraperitoneal administration of opioid receptor antagonist naloxone on beta-endorphin (beta-EP) in blood, pituitary lobes, and placenta as well as splenic natural killer cell activity (NKCA) and placental steroids in pregnant rats at 15-16 days gestation. Two-way analysis of variance revealed significant increases in blood beta-EP induced by heat and naloxone and a significant interaction between heat and naloxone on blood beta-EP and progesterone (P). Whereas heat reduced NKCA, intraperitoneal administration of naloxone reversed it. Significant increases in blood and placental beta-EP induced by both heat and naloxone administration and a significant interaction on blood and placental beta-EP was observed. These results suggest that immunosuppression produced by heat stress during pregnancy is mediated by the opioid system. A positive correlation between beta-EP in blood and placenta during heat and naloxone administration suggests that increased placental beta-EP during heat results in hypersecretion of beta-EP into blood. P increased by heat during pregnancy may be involved in the immunosuppression.

Effects of exposure to microwaves on cellular immunity and placental steroids in pregnant rats

OBJECTIVES

Microwaves produce various detrimental changes based on actions of heat or non-specific stress, although the effects of microwaves on pregnant organisms has not been uniform. This study was designed to clarify the effect of exposure to microwaves during pregnancy on endocrine and immune functions.

METHODS

Natural killer cell activity and natural killer cell subsets in the spleen were measured, as well as some endocrine indicators in blood--corticosterone and adrenocorticotrophic hormone (ACTH) as indices of the hypothalamic-pituitary-adrenal axis--beta-endorphin, oestradiol, and progesterone in six female virgin rats and six pregnant rats (nine to 11 days gestation) exposed to microwaves at 10 mW/cm2 incident power density at 2450 MHz for 90 minutes. The same measurements were performed in control rats (six virgin and six pregnant rats).

RESULTS

Skin temperature in virgin and pregnant rats increased immediately after exposure to microwaves. Although splenic activity of natural killer cells and any of the subset populations identified by the monoclonal antibodies CD16 and CD57 did not differ in virgin rats with or without exposure to microwaves, pregnant rats exposed to microwaves showed a significant reduction of splenic activity of natural killer cells and CD16+CD57-. Although corticosterone and ACTH increased, and oestradiol decreased in exposed virgin and pregnant rats, microwaves produced significant increases in beta-endorphin and progesterone only in pregnant rats.

CONCLUSIONS

Microwaves at the power of 10 mW/cm2 produced activation of the hypothalamic-pituitary-adrenal axis and increased oestradiol in both virgin and pregnant rats, suggesting that microwaves greatly stress pregnant organisms. These findings in pregnant rats suggest that--with exposure to microwaves--pregnancy induces immunosuppression, which could result in successful maintainance of pregnancy. This enhancement of adaptability to heat stress with pregnancy may be mediated by activation of placental progesterone and placental or pituitary beta-endorphin.

Immunisation of chickens to reduce intestinal colonisation with Campylobacter jejuni

1. Systemic and intestinal antibody titres were measured in chickens following subcutaneous, intraperitoneal (i.p.), oral (p.o.) and combined i.p./p.o. administration of antigen, in soluble, emulsified or microparticulate form. Antigens tested included keyhole limpet haemocyanin (KLH), killed Campylobacter jejuni whole cells and purified campylobacter flagellin protein. 2. The effect of immunisation with purified flagellin protein or with killed C. jejuni whole cells in reducing intestinal colonisation was assessed. The ability of newlyhatched chicks to respond to immunisation was limited, possibly because of the immaturity of the immune system rather than maternal suppression of an immune response. Only 5 to 13 birds that were first immunised when 1-d-old with KLH showed a systemic response, even after 4 immunisations, whereas 10 of 11 birds that were first immunised at 24 d-old responded systemically. 3. In an immunisation and challenge experiment, birds that were immunised twice intraperitoneally, at 16 and 29 d-old, with killed C. jejuni whole cells, had fewer C. jejuni, in the caecal contents than unimmunised control birds. This reduction in intestinal colonisation, to less than 2% of bacterial numbers in control birds, was associated with an increase in specific IgG in intestinal secretions. There was no significant increase in specific IgA or IgM in intestinal secretions following immunisation and challenge. 4. These results indicate that immunisation can reduce the level of intestinal infection with C. jejuni. The protection may be enhanced by developing improved methods of immunisation that stimulate production of increased titres of specific antibody in intestinal secretions, particularly specific IgA antibody.

Detection of beta-human chorionic gonadotropin mRNA as a marker for cutaneous malignant melanoma

The beta chain of human chorionic gonadotropin (hCG) hormone is produced by fetal cells, gonadal cell tumors and several types of non-gonadal carcinoma. hCG is composed of an alpha and a beta chain, the latter of which can be used to distinguish the molecule from other related gonadotropin hormones. Detection of beta-hCG mRNA transcripts can be potentially useful as a marker to identify tumor cells. We devised a highly specific and sensitive assay to detect the atavistic expression of beta-hCG in cutaneous melanoma by RT-PCR. Twenty-four melanoma cell lines and 43 melanoma biopsies were evaluated for beta-hCG mRNA expression. An RT-PCR assay was developed to specifically distinguish beta-hCG poly-A mRNA from other related gonadotropin beta chains. This was performed by endonuclease digestion of a unique Sty 1 site in the beta chain, followed by Southern blot analysis with a beta-hCG cDNA probe. Of the 24 melanoma cell lines analyzed, 18 expressed beta-hCG mRNA. Analysis of melanoma biopsy specimens revealed beta-hCG mRNA expression in 17/25 melanoma-positive TDLN, and in only 5/15 non-lymphoid melanoma metastases. Beta-hCG mRNA expression had a 53% correlation to tyrosinase mRNA, a predominant melanoma marker. Beta-hCG mRNA was not detected in normal donor PBL and normal lymph nodes. Detection of beta-hCG mRNA expression may be a useful molecular marker to define a subset of malignant melanoma.

Human pregnancy serum suppresses the proliferative response of lymphocytes to autologous PHA-activated T lymphoblasts

PROBLEM

We have previously demonstrated that human serum can suppress the proliferative response in autologous mixed lymphocyte reaction (AMLR) in which phytohemagglutinin (PHA)-activated T lymphoblasts act as stimulators (T-TPHA AMLR). The aim of the present work was to determine whether pregnancy serum (PS) possesses an inhibitory capacity similar or different in magnitude.

METHODS

Sixteen PS were added to T-TPHA AMLR cultures and the proliferative response was compared with that in the presence of human serum. The effect of PS on the IL-2 dependent proliferation of PHA-activated T Lymphoblasts was examined as well.

RESULTS

PS induced a significantly more pronounced suppression of T-TPHA AMLR than human serum (P < 0.05). One PS tested was not inhibitory but rather stimulatory. This PS was obtained from a woman who subsequently had IUGR. The inhibition is related to the existence of a serum inhibitory factor and not to the lack of a serum supporting factor. PS inhibited not only T-TPHA AMLR of the same woman but also T-TPHA AMLR of other individuals as well, implying that the inhibitor is a non-MHC restricted factor. IL-2 dependent cell proliferation was not inhibited by PS, implying that the inhibitor detected in T-TPHA AMLR is not a general cell proliferation inhibitor.

CONCLUSIONS

These results suggest that a non-MHC restricted inhibitory factor present in PS may play an important biological role in regulating local immune responses in the fetal-placental unit mediated by autoreactive T cells restricted to autologous activated T lymphocytes.

Effect of betamethasone on maternal, fetal and neonatal rat cellular immunity

OBJECTIVE

We evaluated the effect of maternal administration of betamethasone (0.2 mg/kg per day) on mitogen-induced lymphocyte proliferation and interleukin-2 (IL-2) production by maternal, fetal, and neonatal rat splenic lymphocytes.

STUDY DESIGN

Betamethasone was injected intramuscularly on days 19 and 20 of gestation to timed-pregnant rats (Sprague-Dawley). Fetuses were delivered on day 21 of gestation, or allowed to deliver spontaneously at term (22 days), followed by sacrifice at various intervals after birth. Lymphocyte proliferation was determined by 3H-thymidine incorporation with and without phytohemagglutinin (PHA), and IL-2 by proliferation of IL-2 dependent CTLL-2 cells.

RESULTS

Maternal lymphocytes had higher spontaneous proliferation than lymphocytes from nonpregnant female rats. Betamethasone use resulted in a decrease in PHA-induced lymphocyte proliferation and IL-2 production by maternal lymphocytes. These effects were observed until 4 days after delivery. Significant decreases in these parameters were also seen in 21-day fetuses of betamethasone-treated mothers. These effects were still present 6 days after birth but not at 12 days of age.

CONCLUSION

These findings suggest that, in the rat, exposure to betamethasone during late pregnancy results in marked, but transient decreases in PHA-induced lymphocyte proliferation and IL-2 production in both the mothers and their offspring.

Mode of inheritance of HLA haplotypes locus A,B in siblings of different sexes

METHOD

Forty-eight parents and 172 children were typed for class I HLA antigens, locus A,B.

RESULTS

Although the number of cases is small, we observed: (1) a significantly decreased number of sons born after a first delivery of a son, as compared to a first delivery of a daughter; (2) significantly increased sharing of maternal class I HLA antigens between the firstborn son and his brothers from higher birth orders, as compared to his sisters; and (3) HLA-A2 antigen, which is known to be involved in HLA restricted cytotoxic reactions in the recognition of minor histocompatibility antigens, was inherited in subsequent deliveries of sons as compared to daughters in a significantly higher frequency from the paternal than from maternal HLA haplotype. The results suggest that sharing of identical maternal HLA haplotypes between brothers may aid to decrease the degree of maternal sensitization to fetal antigens, and lack of HLA-2 antigen in maternal cells from sons as compared to daughters may avoid maternal HLA-A2 restricted cytotoxic reactions toward the male fetus.

Fetal-maternal immune interaction: blocking antibody and survival of the fetus

In the late 1940s it became clear that the homograft reaction was essentially the result of an immune response. Subsequently, Medawar commented on the apparent paradox of the survival of the mammalian fetus in the face of such a potential (cell-mediated) immune response. In an outbred population the fetal-placental unit will be antigenically different to the mother by virtue of its complement of paternal genes and additionally there may be developmental or stage-specific gene products that are immunogenic. Many mechanisms have been proposed to account for the survival of the fetus in the face of a potential immune attack and, while many of these have been investigated in considerable detail, there has been no clear-cut indication that any one plays a predominant role. Either control of immune rejection of the fetus is exercised by an as yet undiscovered mechanism or, more probably, by a combination of some or all of the mechanisms that have been proposed by many workers over the last three decades. Potential controlling processes, which will be reviewed briefly, include: systemic and local modification of maternal responsiveness; altered expression of MHC antigens on extra-embryonic tissues; the placenta as a barrier; and blocking antibody responses. We discuss some of our recent studies in which we have started to look for potential blocking antibodies in a mouse model system. Cells secreting immunoglobulins M and G, characterized in hemolytic plaque assays, have been mapped to areas close to the midgestation mouse embryo, using an immunocryohistological technique. A scaled-down version of hybridoma technology has been used as an analytical probe of the specificity and isotype of immunoglobulin secreted by cells originating either from close to the embryo/fetus or from the para-aortic lymph nodes (PALN). So far monoclonal (IgG1) antibodies with specificity for embryonic cells have been derived together with some monoclonal immunoglobulins with as yet uncharacterized antibody specificity.

Cytotoxic T lymphocyte responses in the peripheral blood of children born to human immunodeficiency virus-1-infected mothers

Cytotoxic T lymphocytes (CTL) are present at high activities in adult patients infected with the human immunodeficiency virus (HIV). In this report, CTL effectors were identified in peripheral blood mononuclear cells (PBMC) of children born to HIV-1-infected mothers. These CTL killed HLA-matched HIV-1-infected H9 target cells or doubly transfected P815-A2-env, gag or nef mouse tumor cells, which expressed the viral antigens in association with HLA-A1/A3 or HLA-A2, respectively. HIV-1-specific CTL were detected early after birth (less than 2 months) and remained present during the asymptomatic phase of the infection. As in HIV-1-infected adults, HIV-specific CTL declined with disease progression. Surprisingly, HIV-1-specific CTL were detected in the PBMC of three children who subsequently became seronegative.

Autoantibodies to c-myc protein: elevated levels in patients with African Burkitt's lymphoma and normal Ghanians

Sera from U.S. patients with SLE, RA, and various malignancies, clinically normal individuals with sero-activity to HIV, AIDS, and from pregnant women were tested for the presence of anti-c-myc antibodies. In an ELISA using recombinant human c-myc protein as the antigen, no difference in mean antibody titer was generally detected in these sera when compared to normal controls. Only three malignancy sera (two myeloid leukemia and only one lymphoma) and two patients with AIDS-related lymphoma exhibited exceedingly higher levels of anti-c-myc antibody. However, significantly elevated anti-c-myc antibody levels were found among 20 patients with African Burkitt's lymphoma (Ghana) and 20 normal Ghanians, thus apparently reflecting an autoimmune phenomenon prevalent in the endemic region. These findings indicated that elevated levels of anti-c-myc antibodies are not a general characteristic of patients with diseases that have been associated with increased expression of c-myc.

Anti-idiotypic IgM antibodies to anti-HLA class I antibodies in habitual abortion

In order to investigate the role of the idiotypic network in miscarriages, sera from 28 habitually aborting women undergoing paternal leukocyte immunization were studied for the presence of HLA antibodies and related anti-idiotypes. Sixty-eight percent of sera from preimmunized patients which did not contain anti-lymphocyte antibodies inhibited the activity of antibodies to the HLA class I antigens expressed by the spouse. This inhibitory activity could be assigned to IgM antibodies, which cross-inhibit antibodies of similar specificity. This suggests that they are anti-idiotypes for the binding site of HLA antibodies. Immune sera of successfully treated patients exhibited both cytotoxic IgG anti-HLA antibodies and inhibitory IgM anti-idiotypic antibodies. A possible role for an intact idiotypic network in maintaining pregnancy is suggested.

Expression of transferrin receptor on human maternal and neonatal peripheral blood lymphocytes

The levels of peripheral blood lymphocytes expressing the receptor for transferrin (TSR) on untreated and phytohemagglutinin (PHA)-stimulated cell samples from maternal-neonate pairs were evaluated 4-12 h postpartum. Significantly increased levels of TSR+ cells were observed on fresh, unstimulated neonatal and maternal cells, as compared to control cells from young adult males and females, and the values seemed to correlate with the sex of the neonate and with birth order. The level of TSR+ cells in culture was found to be increased on neonatal cells and decreased on maternal cells.

Effects of short-term administration of human chorionic gonadotropin on immune functions in cryptorchid children

To delineate the effects of human chorionic gonadotropin (hCG) administration on immune responsiveness, immunological parameters including serum immunoglobulins, total and differential white blood cell count T and B lymphocyte membrane phenotype, in vitro, proliferative response to phytohaemagglutinin, Concanavalin A (ConA) and pokeweed mitogen were studied in 13 prepubertal cryptorchid boys before, during, and 3 months after hCG therapy. Before treatment, all the immunological parameters were normal except for an unexpected high percentage of T suppressor-cytotoxic cells (CD8+). During therapy, the absolute number of total peripheral blood lymphocytes, and that of total T-cells, T helper-inducer cells and of CD8+ subsets were diminished. The percentage of CD8+ cells and lymphocyte response to ConA decreased significantly and returned to normal after hCG withdrawal. The possible effects of long-term hCG treatment remain to be determined.

Immunological factors responsible for pathogenetic cell degeneration in pregnancy

The placenta has an important role as an immunological barrier during pregnancy. When the placental barrier is disrupted, materno-embryonic transfusion takes place. Several clinical reports relate congenital malformations or abortion to intrauterine bleeding or transplacental transfusion. In an earlier experiment, pathogenetic cell degeneration was induced using an in vitro whole rat embryo culture. Transplacental transfusion was simulated by intracardiac injection of an allogeneic rat-antirat serum directed against the blood group antigens. The present study examines the morphological and immunological effects on the development of rat embryos 9 to 10 days old (stages 8-10 somites) of the separate administration of primary allogeneic antisera, obtained 10-17 days after immunization, and secondary allogeneic antisera, obtained after booster immunization on day 45-52. Rat-antirat alloantibodies were directed against the blood group antigens. Transplacental transfusion was simulated by the embryonic intracardiac microinjection of approximately 0.5 microliters serum enriched with either primary or secondary obtained allogeneic antibodies. After 48 hours' incubation, the embryos were examined microscopically, and it appeared that the secondary antisera, which had hemolytic activity, was more potent (P less than 0.005) in the induction of pathogenetic cell degeneration. It is well known that IgG antibodies display hemolytic activity. This finding was confirmed by direct immunofluorescence performed on rat embryos 2, 4, and 6 hours after injection, where incubation with rabbit-antirat anti-IgG antibodies gave a strong reaction. The hypothesis discussed is whether or not pathogenetic cell degeneration subsequent to transplacental transfusion of maternal antibodies can be initiated by similar immunological events.

Immune responsiveness of neonatal chicks and immunocyte precursors from unprimed juvenile chicken donors

The immune responsiveness of immunocyte precursors, obtained from peripheral blood of 4- to 6-wk-old unprimed chickens and assayed with the cell transfer model, was compared with that of neonatal chicks. Little if any splenic plaque-forming cell (PFC) production was observed in the spleens of embryonic cell transfer hosts following a single antigen exposure to weak or moderate dosages of mammalian erythrocytes. However, modest to high PFC formation occurred consistently in the hosts following a second exposure to the same antigen when given 3 days later. Although a single immunization failed to elicit PFC formation in embryo hosts, a single injection of a wide range of antigen dosages into 8-day-old chicks elicited PFC production consistently. When the double immunization protocol was used with 2- to 9-day-old neonatal chicks, the level of immune responses were indistinguishable from those elicited with a single antigen injection. The difference in the immune kinetics observed in embryo hosts may be related to the embryonic microenvironment, which is permissive, but may not be as immunosupportive as that of neonates.

Immunoregulatory mechanisms present in the maternal circulation during pregnancy

Systemic alterations of the maternal inflammatory and immune system occur during pregnancy. These changes alone are unlikely to be responsible for the acceptance of the fetal semiallograft. Numerous local events at the maternal-fetal interface appear to be more important. The alterations of the maternal inflammatory and immune systems are subtle enough for no significant increase of infections or malignancy to be apparent. However, 75% of women with rheumatoid arthritis are clinically improved during pregnancy. The effects of pregnancy on polymorphonuclear cells are not likely to be responsible because cell function actually appears enhanced in vivo, despite the fact that pregnancy serum is suppressive in vitro. There is no clear evidence for reduction of monocyte/macrophage function during pregnancy, either in vivo or in vitro. It is unlikely that modulation of B cell phenotype or function is responsible because no suppression is noted, either in vivo or in vitro. Selected products of B cells, immune complexes, appear to be reduced during pregnancy. In patients, the reduction in the concentration of complexes may be due to adsorption by the placenta. The importance of this reduction as a causative factor in the improvement of women with rheumatoid arthritis during pregnancy remains to be determined. Natural killer cell cytotoxicity is decreased during pregnancy. This may in part be due to the release of progesterone induced blocking factor. It is also possible that circulating factors, capable of inhibiting IL-2 release or IL-2 function in vivo, might be responsible. Natural killer cytotoxicity can be normalized by incubation with IL-2. It is unclear how the reduction of natural killer cell activity might systematically affect inflammation or immunity in vivo during pregnancy. In vivo delayed type hypersensitivity appears somewhat reduced during pregnancy. This observation appears consistent with the improvement of rheumatoid synovitis, which is also thought to be T cell mediated. T cell function, measured in vitro, generally appears normal. However, most recent studies have employed mitogens, such as PHA, which is not physiological. Subtle defects involving antigen processing or antigen presentation might be missed in this system. These observations suggest that circulating factors might be important in modulating the cell mediated immune system, in vivo, during pregnancy. While anti-HLA-DR antibodies eluted from the human placenta may be effective therapy in patients with rheumatoid arthritis, their occurrence is too infrequent to account for the improvement seen in afflicted patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of different procedures of semen preparation on antibody-coated spermatozoa and immunological infertility

To assess whether procedures of semen preparation can reduce the proportion of antibody-coated spermatozoa, semen samples with positive direct mixed antiglobulin reaction (MAR) were washed in media supplemented with 10% or 50% fetal cord serum (FCS). Washing reduced the MAR to a negative level, but the MAR was identical to that in the native semen when spermatozoa were resuspended in serum-free medium. Donor spermatozoa, recovered after swim-up in media supplemented with 10% or 50% FCS or after passage through a column with 7.5% human serum albumin (HSA), were incubated in serum samples with both agglutinating and cytotoxic antisperm antibodies. Cytotoxic activity was significantly reduced against sperm filtered over the albumin column.

Changes in maternal and newborn lymphocyte reactivity in reciprocal mixed lymphocyte cultures during the postpartum period

Reciprocal one-way mixed mother-newborn lymphocyte cultures (MMNLC) containing alternatively maternal or newborn responding (R) or stimulating (S) cells were investigated in both directions in primiparae at three different times: a few hours after delivery, and at 4 and at 16 weeks. Cultures were grown in the presence of maternal and pooled control serum prepared from the blood of five to eight unrelated healthy donors. Four weeks after delivery in maternal and in control serum a significant increase in MMNLC reactivity could be observed, which disappeared at 16 weeks when a pronounced decline in MMNLC values in both directions was found. The suppressive effect of maternal serum was more pronounced at delivery, still evident 4 weeks later, and insignificant after 16 weeks. The results of this study suggest that 4 weeks after delivery, maternal sensitization to fetal histocompatibility antigens can be detected in primiparae with MMNLC; and that 16 weeks later, this was no longer detectable with the same test.

Autologous mixed lymphocyte reaction in human neonatal lymphocytes

Human neonatal mononuclear cells were examined to determine their ability to participate in an autologous mixed lymphocyte reaction (AMLR). Stimulator cells were isolated by plastic adherence and nylon wool adherence. The nylon wool-nonadherent cells were used as responder cells. In 10 of 10 neonatal samples and 6 of 7 adult samples, a significant AMLR was present when plastic-adherent cells were used as stimulators. Neonatal blood showed a mean increase in proliferation of 7.6 (3.6-14.9), while adult cultures showed a mean stimulation index of 11.8 (1.0-39.0). When nylon wool-adherent cells were used as stimulator cells, only 2 of 7 neonatal blood samples and 1 of 5 adult blood samples showed a significant AMLR. When recombinant interleukin 2 (IL-2) was added to AMLR cultures of plastic-adherent cells and nylon wool-nonadherent cells, a mean augmentation of 12.0 was seen in the neonatal AMLR, while the adult cultures were augmented by a mean response of 4.1. Addition of IL-2 to nylon wool-nonadherent cells alone produced a 5.9-fold increase in adult cells, while neonatal cells showed an 85.8-fold mean increase in proliferation. The results suggest that autoreactive T cells are present in neonatal blood and that these cells can be activated by plastic-adherent autologous cells. However, neonatal and adult nylon wool-adherent cells do not consistently activate autoreactive T cells.

Trophoblast-derived immunoregulatory factor: demonstration of the biological function and the physicochemical characteristics of the factor derived from choriocarcinoma cell lines

An immunosuppressive factor released by choriocarcinoma cell lines was analyzed in the present study. It inhibited the proliferative responses of human T cells stimulated by lectins or alloantigens. It also blocked the generation of alloreactive cytotoxic T cells. The suppressive activity of the factor was detected in the responses of the T cells costimulated with 1 nM 12-O-tetradecanoyl phorbol 13-acetate and 1 microM A23187, suggesting the possibility that the factor acted on the intracellular signal transduction in T cells rather than interfering with early events such as T cell receptor signal transduction through cell membranes. Moreover, the factor acted directly on T cell proliferation pathways without activation of suppressor cells but did not act on T cell activation pathways. Taken together, all these findings expanded our previous reports on a factor released by normal trophoblasts, indicating the possible identity of the two factors. The physicochemical properties of the choriocarcinoma-derived factor were examined, and the biological significance of the factor during pregnancy was discussed in this paper.

The interleukin 2 gene is expressed in the syncytiotrophoblast of the human placenta

The lymphokine interleukin 2 is an important immune system regulatory glycopolypeptide. It is produced by antigen- or mitogen-stimulated T lymphocytes and is required for the proliferation or clonal expansion of activated T lymphocytes. In this report, it is demonstrated by RNA transfer blot hybridization that the poly(A)+ RNA population of the human placenta contains a 0.85-kilobase RNA transcript that specifically hybridizes to a human interleukin 2 cDNA probe. By using hybridization histochemistry in situ, it is further shown that interleukin 2 RNA transcripts are localized, primarily, to the syncytial (syncytiotrophoblast) layer of the human placenta. Possible roles for syncytiotrophoblast-produced interleukin 2 are suggested and discussed.

Immunoregulation of luteolysis

It is proposed that the immune/inflammatory system plays a yet unrecognized role in the mechanics of prostaglandin (PG) F2 alpha-induced luteal regression. Eosinophils are specifically attracted into luteal tissues and activated to degranulate (i.e. secrete cytotoxins) before symptoms of luteolysis are manifested (sheep). Further, because eosinophils are often associated with tissue reactions involving antigen-antibody binding, it is hypothesized that a luteal cell antigen could be expressed/unmasked as a result of the action of PGF2 alpha. Identification of the antigen by an appropriate autoantibody (e.g. complement-fixing) is an alternative mode by which cellular destruction can be mediated. Sialic acid residues that coat the surface of luteal membranes might act as a protective agent to autoimmune recognition. The hypothesis that luteolysis comprises an autoimmune reaction is extended to indicate that rescue of the corpus luteum from regression during early pregnancy involves a local immunosuppressive mechanism.

Induction of B cell unresponsiveness to noninherited maternal HLA antigens during fetal life

Patients who have received many transfusions become highly sensitized and develop antibodies against almost all HLA alloantigens, so that finding a cross-match negative kidney donor is difficult. A survey of those patients showed that 50 percent did not form antibodies against the noninherited maternal HLA antigens. Apart from the obvious clinical implications, the data indicate that a human equivalent of murine neonatal or actively acquired tolerance has now been identified.

Identification of a histamine-releasing factor secreted by human pre-implantation embryos grown in vitro

Human pre-implantation stage embryos cultured in vitro spontaneously secreted a factor capable of inducing histamine-release from human blood basophils. The embryo-derived histamine-releasing factor (EHRF) has been isolated from the culture medium by means of heparin-Sepharose affinity chromatography. The factor bound to the column and was then eluted by increasing the buffer molarity to 1.5 M NaCl. EHRF was detected using an enzymatic-isotopic microassay and sensitized basophils known to undergo release with anti-IgE. The EHRF-induced histamine-release was calcium and temperature dependent and the relatively slow kinetics (10 min) were similar to those obtained with anti-IgE. EHRF caused the release of a substantial amount of histamine (48%, n = 18) in a dose-dependent manner. The equivalent fraction isolated from medium containing unfertilized oocytes gave less than 10% of histamine-release using the same source of basophils, suggesting that EHRF was secreted after fertilization. EHRF was very stable since it was resistant to boiling, lyophilization, and to several freeze and thaw treatments. The histamine-releasing activity induced by EHRF was measured in vitro also by means of purified leukocytes containing sensitized basophils. EHRF could represent a message sent by the embryo to the mother to induce histamine release at the time of implantation.

Maternal autoimmune disease influences self-tolerance in offspring: the role of suppressor cells and materno-foetal cell traffic

Autoimmune haemolytic anaemia (AIHA) was induced in normal strain (CBA/Ca/T6) mice by repeated intraperitoneal injection of rat red blood cells (RRBC). Antibody production to cross-reactive antigens on mouse red blood cells (MRBC) and foreign antigens on RRBC was measured by the direct antiglobulin test (DGAT) and serum haemagglutination, respectively. RRBC primed female or male mice and sheep red blood cell (SRBC) primed controls were mated with naive partners and their progeny immunized with RRBC in adult life. The offspring of mothers but not fathers with active autoimmune disease showed a significant reduction in antibody response to self (MRBC) antigens, whereas the response to non-self (RRBC) was unaffected. Transfer of 30 X 10(6) spleen cells from the progeny of RRBC primed mothers into non-irradiated normal recipients resulted in selective suppression of the anti-self response following challenge with RRBC, provided that the cell donors had been boosted with RRBC 7-10 days before the transfer was performed. Thus the progeny of mothers with AIHA possessed self-reactive memory suppressor cells (Ts) shown previously to belong to the Thy-1+ I-J+ Ly-2+ T cell subset in this model. To test whether the Ts were of maternal or foetal origin the suppressor assay was repeated with spleen cells from the F1 offspring of RRBC primed B10.A(3R) (I-Jb) mothers and normal CBA(I-Jk) fathers. Pretreatment with anti-I-Jb serum plus complement completely abrogated suppression on adoptive transfer but anti-I-Jk serum failed to do so, indicating that the Ts were derived from the mothers. These findings emphasize the potential importance of Ts in induction of self tolerance during early ontogeny.

Immune response of the atopic woman and foetus: effects of high- and low-dose food allergen intake during late pregnancy

The influence of the mother's consumption of cows' milk and hens' egg on the immune response (IgE, IgG) in the mother and foetus was studied in 165 pregnant women with atopical respiratory disease with an allergy to pollen and/or animal dander. The women were randomly allocated to four diets ranging from a diet free from hens' egg and cows' milk to a diet containing intake of one egg and one litre of milk daily during the third trimester. No significant differences in cord blood IgE levels were noted in spite of differences in maternal diet, and no specific IgE antibodies to ovalbumin, ovomucoid and betalatoglobulin were found in the cord blood. The mother's IgG antibody concentrations to ovalbumin, ovomucoid and betalactoglobulin were influenced by her diet, but cord blood IgG antibody levels to the selected food allergens were unaffected. The data presented on the IgE and IgG antibody levels to ovalbumin, ovomucoid and betalactoglobulin in cord blood suggest that changes in maternal diet during the last trimester of pregnancy in order to prevent atopic sensitization in utero are less likely to affect the foetus than previously supposed.

Maternoembryonic transfusion and congenital malformations: an experimental study using rat embryos

In an experimental study, using an in vitro whole rat embryo culture, the effects of a maternoembryonic transfusion and immunologic interaction on the development of ten-day-old rat embryos (stages 8 to 10 somites) has been studied. Transplacental transfusion has been simulated by embryonic intracardiac microinjection of 0.1 to 0.5 microL immunologically active rat serum. After an incubation of 24 and 48 hours, respectively, the embryos were killed. All tested embryos have survived the incubation period. On microscopic examination of the tested embryos those that were taken from the incubator after 24 hours showed no signs of pathogenic cell degeneration, while the embryos that were taken from the incubator after 48 hours all had localized lesions with pathogenic cell degeneration in one or multiple major structures. The neurectoderm and endoderm seem to be the most sensitive tissues in this period of organogenesis. The results suggest that immunologic reaction to transplacental transfusion of maternal serum may lead to congenital malformations.

Antibodies to the oral bacterium Streptococcus mutans and the development of caries in children in relation to maternal dental treatment during pregnancy

These factors were studied in 50 children, aged 3.6 to 5.9 years. Children of mothers who had no dental treatment during pregnancy (NTP-group, n = 25) had significantly (p less than 0.02) more serum IgG antibodies reactive with Strep. mutans than those of mothers who received such treatment (TP-group, n = 25). The children in the NTP-group had fewer Strep. mutans, a higher proportion of intact dentitions, lower dmfs/DS-index and lower caries incidence than those in the TP-group. Over one year of follow-up, a significantly greater proportion of children in the TP- than in the NTP-group developed new caries (p less than 0.05). Thus, maternal dental treatment during pregnancy may affect caries development in the primary dentition of the child, possibly via transplacental immune mechanisms.

Serum- and cell-mediated immune protection of mouse placenta and fetus against a Brucella abortus challenge: expression of barrier effect of placenta

When mice are intravenously inoculated with a virulent Brucella abortus strain at day 12 to 14 of pregnancy and killed three to five days later, colonization of placentae, fetuses and spleens can be estimated by the frequency and level (bacterial count) of infection and by linkage between individual placental and paired fetal infections. This linkage indicates the placental barrier effect, defined as the number of non-infected fetuses linked to 100 colonized placentae. Immune mice serum raised against two Brucella fractions injected one day before challenge (1) restricted the placental colonization (the dose required to infect 50 per cent placentae was increased by 50 to 70 times compared to controls), (2) decreased the level of splenic and placental infection, and (3) increased the barrier effect so that most fetuses were protected even when linked to a heavily infected placenta. Immune (B + T) spleen cells from mice vaccinated with a Brucella cell-wall fraction transferred to recipients seven to eight days before mating, that is, 22 days before challenge (1) restricted the frequency of placental and fetal colonization, (2) decreased the level of splenic, placental and fetal infections, and (3) increased the barrier effect. However, separated B- and T-cells were less active, in particular on the level of fetal infection. In contrast with serum, the cells did not decrease infection of the fetuses linked to heavily infected placentae.

Treatment of sheep with prostaglandin F2 alpha enhances production of a luteal chemoattractant for eosinophils

Eosinophils were quantitated in sections of luteal tissue obtained from sheep treated with a luteolytic dose of prostaglandin (PG) F2 alpha. Increased numbers of cells were detected before the onset of either functional (decline in sera or tissue concentrations of progesterone) or morphological regression. Luteal tissue was shown to produce a specific chemoattractant for eosinophils as assessed by a linear under-agarose migration assay. Eosinophils were responsive toward leukotriene B4, but not toward PGF2 alpha or a synthetic N-formyl peptide. Because eosinophils are capable of mediating tissue damage in immune/inflammatory conditions, it is suggested that these cells could play a similar role in the mechanics of luteolysis.

Cytotoxic sperm antibodies and in vitro fertilization of mature oocytes: a preliminary report

The fertilization rates of mature oocytes during in vitro fertilization and embryo transfer (IVF-ET) using fetal cord serum-supplemented insemination media were greater than or equal to 57% for five infertile couples without sperm antibodies (group 1). But they were less than or equal to 50% for four of nine infertile couples (group 2) with cytotoxic sperm antibodies in both partners (n = 6) or the husband alone (n = 3). Two women in group 1 were successful in achieving normal, full-term pregnancies with the delivery of normal infants (chi2 = 4.2, P less than 0.05, by chi-square analysis). One of them consistently tested negative for sperm antibodies, while her husband was previously treated with antibiotics for infection and transient sperm antibodies in the seminal plasma. Subsequently, antibody titers in the husband were in the normal range when the successful IVF-ET was performed. One woman in group 2, with antibodies to her autoimmune husband's sperm but not control sperm and with a long-standing poor postcoital test sperm motility, conceived through artificial insemination with donor sperm (AID) after failing to conceive with her husband through IVF-ET. These data suggest that the presence of cytotoxic sperm antibodies in the serum and/or secretions of both partners reduces the rates of fertilization of mature oocytes in spite of using fetal cord serum in the IVF media. Pregnancy achievement is impaired in this group.

Phenotypic heterogeneity and recycling capacity of natural killer cells in normal human pregnancy

Natural killer (NK) cells have the ability to kill a variety of target cell types and the possibility that such cells could mount an effective attack on the developing fetus has not been discounted. The present study extends previous work showing that maternal NK reactivity against K562 target cells (TC) is reduced during pregnancy. Here we demonstrate using cytotoxicity assays at both the population and single cell level that, although depressed in number, maternal NK cells exhibiting the capacity to kill K562 TC are as lytically active in their ability to recycle and destroy multiple TC as NK cells from non-pregnant females. Moreover, two colour immunofluorescence analysis of the NK cell-associated markers Leu-7 and Leu-11b indicates that, in addition to a reduction in the absolute number of TC conjugate-forming cells, pregnant females present in their peripheral blood a larger proportion of TC-binding Leu-7+11- cells. These cells may be lytically immature. Small changes in NK cell profile and activity in maternal peripheral blood may be indicative of much more significant changes at the feto-maternal interface. It is, however, clear that pregnant females retain a population of highly active NK cells, thus minimising the possibility of immunocompromise.

Effect of a soluble factor secreted from cultured human trophoblast cells on in vitro lymphocyte reactions

The immunoregulatory role of trophoblast cells in cell-mediated immunity was investigated. Trophoblast cells were obtained from 8-10-week human placentae by treatment with collagenase followed by differential centrifugation. The cells were cultured for 48 hr, and the culture supernatant was examined for immunosuppressive activity in vitro. The supernatant when added to cultures of peripheral blood lymphocytes from healthy donors suppressed both their reactivity to different lectins (PHA and PWM) and their activity in one-way mixed lymphocyte reaction. The degree of suppression was dose-dependent. Furthermore, the supernatant was able to reduce the natural killer cell activity against K562 target cells. On the other hand, the supernatant had no inhibitory effect on the effector phase of lymphocyte-mediated cytotoxicity activity against tumor cell lines RPMI 8866 and Daudi. In all cases, the suppression observed was not due to lymphocytotoxicity or tumor cell mortality. The results indicate that trophoblast cells release a soluble suppressive factor that is a potent inhibitor of cell-mediated immunity.

Chronic inflammatory demyelinating polyradiculoneuropathy associated with pregnancy

In a series of 61 patients with the relapsing variety of chronic inflammatory demyelinating polyneuropathy, there were 16 women of childbearing age, 9 of whom became pregnant. In 4 of these women, the onset of neuropathy occurred in pregnancy and in the other 5 relapses occurred during pregnancy. There was a significant increase in the number of relapses during the year of pregnancy, and a tendency for symptoms to worsen during the third trimester or immediate postpartum period. It is concluded that there is an increased risk of relapse of chronic inflammatory demyelinating polyneuropathy in pregnancy.

Phenotypic dissection of cord blood immunoregulatory T-cell subsets by using a two-color immunofluorescence study

Expression of TQ1(Leu8) and 2H4 antigens on human cord blood T-cell subsets was evaluated by a double immunofluorescence analysis. In normal adult blood all of the helper function for B-cell differentiation is confined to the smaller OKT4+TQ1-(Leu8-) cell subset, while the OKT4+TQ1+(Leu8+) cell subpopulation includes a subset of suppressor inducer 2H4+(JRA+) cells. Our results indicated that the OKT4+TQ1-(Leu8-) cell subpopulation was decreased and the reciprocal OKT4+TQ1+(Leu8+) cell subset was markedly increased in cord blood E-rosetting OKT3+ cell population. A rise in the number of cord OKT4+2H4+ cells was also found. In addition, TQ1 antigen was present on OKT3+E-, a less mature, cord T-cell subset, not present in adult blood. These findings may not only be of help in understanding lymphoid cell development during ontogeny, but also may agree with the reported strong-suppressor and weak-helper activities exerted by the T-cell subsets circulating in human cord blood.