O feto é um ser alogênico de sucesso / The fetus is a successful allogeneic being

O feto é um ser alogênico de sucesso. O feto é um aloenxerto natural bem tolerado pelo organismo materno. Vários fatores contribuem para a tolerância materna ao feto: 1. O útero é um local do corpo imunologicamente privilegiado, protegido por uma barreira tecidual não imunogênica; 2. A promoção de uma resposta imunossupressora local pela mãe: a. A molécula HLA-G do MHC de classe Ib, expressa nas células da placenta, impede que as células NK matem a placenta; b. A catabolização do aminoácido essencial triptofano pela placenta impede que as células T da mãe tenham acesso ao feto; c. A secreção das citocinas TGF-ß, IL-4 e IL-10, pelo epitélio uterino e trofoblasto, tende a suprimir as respostas das células T da mãe; d. A secreção das citocinas TGF-ß e IL-10, pelas células T reguladoras, também inibe as respostas de células T maternas.(AU)

The fetus is a successful allogeneic being. The fetus is a natural allograft well tolerated by the maternal organism. Several factors contribute to maternal fetal tolerance: 1. The uterus is an immunologically privileged body site, protected by a non-immunogenic tissue barrier. 2. Promoting a local immunosuppressive response by the mother: a. The MHC class Ib HLA-G molecule, expressed on placental cells, prevents NK cells from killing the placenta; b. The catabolization of the essential amino acid tryptophan by the placenta prevents the mother's T cells from accessing the fetus; c. Secretion of TGF-ß, IL-4 and IL-10 cytokines by the uterine and trophoblast epithelium tends to suppress the T-cell responses of the mother; d. Secretion of TGF-ß and IL-10 cytokines by regulatory T cells also inhibits maternal T cell responses.(AU)

Índice de massa corporal, circunferência da cintura e hipertensão arterial em estudantes / Índice de masa corporal, circunferencia de la cintura y hipertensión arterial en estudiantes / Body mass index, waist circumference, and arterial hypertension in students

RESUMO Objetivo: investigar qual o melhor preditor antropométrico de hipertensão arterial em alunos de escolas privadas. Método: estudo transversal, com amostra composta por 286 alunos com idade de 10 a 14 anos de duas escolas privadas de Paranavaí-Paraná. As variáveis analisadas foram: índice de massa corporal, circunferência de cintura e pressão arterial. Na análise estatística foram utilizados os testes de correlação parcial de Pearson e a regressão logística multivariada, considerando-se p<0,05. Resultados: os dois indicadores antropométricos demonstraram fracas correlações com os níveis sistólicos e diastólicos, com coeficientes (r) variando de 0,27 à 0,36 (p< 0,001). Na análise multivariada, o único indicador antropométrico associado ao risco de hipertensão arterial foi a circunferência de cintura (OR= 2,3; IC 95%: 1,1-4,5) independente da idade e gênero. Conclusão: nesta faixa etária, a circunferência de cintura parece ser melhor do que índice de massa corporal como preditor de hipertensão arterial. .

RESUMEN Objetivo: investigar cuál es el mejor predictor antropométrico de la hipertensión arterial en los alumnos de escuelas particulares. Métodos: estudio transversal con muestra compuestas por 286 alumnos con edad de 10 a 14 años de dos escuelas privadas de Paranavaí-Paraná. Las variables analizadas fueron: índice de masa corporal, circunferencia de la cintura y la presión arterial sistólica y diastólica. En el análisis de estadísticas fueron utilizadas las pruebas de correlación parcial de pearson y regresión logística multivariada considerándose p<0.05. Resultados: los dos indicadores antropométricos han mostrado débiles correlaciones con los niveles sistólicos y diastólicos, con Coeficientes (r) variando de 0,27 a 0,36 (p<0,001). En el análisis multivariado el único indicador antropométrico asociado al riesgo de hipertensión arterial fue la circunferencia de la cintura (OR=2,3; IC 95%: 1,1- 4,5) independiente de la edad y el género. Conclusión: en este grupo de edad, la circunferencia de la cintura parece ser mejor de que el índice de masa corporal como predictor de la hipertensión arterial. .

ABSTRACT Objective: to investigate what is the best anthropometric predictor of arterial hypertension among private school students. Method: this was a cross-sectional study with 286 students between the ages of 10 and 14 from two private schools in the city of Paranavaí, Paraná, Brazil. The following variables were analyzed: body mass index, waist circumference and blood pressure. Statistical analysis was conducted with Pearson’s partial correlation test and multivariate logistic regression, with p<0.05. Results: both anthropometric indicators displayed weak correlation with systolic and diastolic levels, with coeffi cients (r) ranging from 0.27 to 0.36 (p < 0.001). Multivariate analysis showed that the only anthropometric indicator associated with arterial hypertension was waist circumference (OR= 2.3; 95% CI: 1.1-4.5), regardless of age or gender. Conclusion: this age group, waist circumference appeared to be a better predictor for arterial hypertension than body mass index. .

Inmunología perinatal / Perinatal immunology

Se ha considerado que el útero gestante es un lugar inmunológicamente privilegiado, donde el feto es protegido del rechazo por el sistema inmune materno, mediante un amplio repertorio de estrategias de evasión que contribuye a la sobrevivencia del feto. La gestación en sí misma constituye un acontecimiento de equilibrio inmunológico y la tolerancia inmunológica permite la progresión del embarazo, donde participan una secuencia sincronizada de eventos que se inicia desde la concepción y fertilización para dar lugar a la implantación y progresa hasta alcanzar un embarazo a término. El sistema inmune es la principal barrera que poseemos para protegernos de las infecciones. Durante la vida intrauterina, el feto está protegido por la madre de las agresiones externas, por lo que no necesita que su sistema inmunológico sea operativo, sin embargo, al nacer, recibe una avalancha de elementos extraños, por lo que necesitará disponer de cierta protección, así como una preparación para ejecutar las defensas necesarias para su protección inmunológica. La inmunidad sérica durante la vida fetal queda limitada a la transferencia a través de la placenta de IgG materna, a pesar de que el feto tiene la facultad de sintetizar inmunoglobulinas desde las primeras etapas de la gestación. Al nacimiento, el niño tiene su sistema inmunológico completo, aunque inmaduro, pero es capaz de responder a los estímulos antigénicos. Tiene múltiples anormalidades en el desarrollo de su sistema inmune, que involucran a los anticuerpos/inmunoglobulinas, complemento y granulocitos pudiendo contribuir a la alta incidencia de sus infecciones. El recién nacido carece de memoria inmunológica debido a que, en condiciones normales, el feto está exento de estímulos producidos por antígenos extraños. Dicha memoria se va adquiriendo a medida que entra en contacto con los diferentes antígenos. Se obtendrá cierta protección a las infecciones entéricas gracias a las IgA que aporta la lactancia materna. La exposición prenatal y postnatal a productos microbianos ambientales que pueden activar la inmunidad innata, puede acelerar el proceso de maduración del sistema inmune.(AU)

It has been considered the pregnant women`s womb as an immunological exceptional place, where fetus is protected against been rejected because of maternal immune system by means of a wide groups of evasive strategies that help in its survival. Pregnancy itself is an immunological equilibrium state and the immunological tolerance allow the progression of this event, where participate a synchronized sequence of biological events started from conception and fertilization to allow the implantation, and progress until to reach the pregnancy end. The immune system is our main barrier against infections. During intrauterine life fetus is protected by the mother against external aggressions, therefore he don`t need an operative immune system, nevertheless, at birth the new organisms receive an avalanche of strange elements needing some kind of protection as well as a preparation to carry out the necessary defense for his immunological protection. Serum immunity during fetal life is limited to the transference of maternal IgG through placenta, despite fetus capability to synthesize immunoglobulins from first stages of gestation. At birth the babe has a complete immunological system although immature but capable to respond to antigenic stimulus. He has multiples abnormalities in the immune system development that take account antibodies/immunoglobulin, complement and granulocytes contributing to his high incidence of infections. Newborn lack immunological memory because in normal conditions fetus is not stimulated by odd antigens. This memory is acquired through the contact with different antigens. It will be obtained some protection against enteric infections because IgA from maternal lactation. The prenatal and postnatal exposition to environmental microbial products that activate the innate immunity can accelerate the immune system maturing process.(AU)

Feto-maternal interactions and immunological tolerance of the mother to her semiallogeneic fetus

Pregnancy is a cooperative interaction between the mother and her fetus, allowing survival and normal growth of the fetus. Successful pregnancy remains a fascinating phenomenon as it resists the immunological rules of rejection. Immunological recognition of the fetus is vital for maintenance of gestation. The maternal immune system undergoes changes that lead to tolerance of the fetus. Inadequate recognition of fetal antigens may cause abortion. In fact, fetal cells express paternal alloantigens that are not recognized as foreign by the mother. A special balance between lymphocytes is present at the feto-maternal interface to control the immune response. In addition, placenta! trophoblasts act as a physical barrier and exert an immunoregulatory function. Trophoblast cells regulate the expression of human leucocyte antigens. Dysfunction of these cells leads to morphological and functional alterations of the feto-maternal barrier as well as to recurrent spontaneous abortions. Uterine natural killer cells are appropriate residents of the materno-fetal interface to support the adaptation of the blood vessels of the pregnant uterus and regulate trophoblast invasion into the decidua and myometrium. Cytokines are involved at the feto-placental unit by adapting normal T-cell trafficking and modulating the inflammatory process. This study discusses the complex immunological aspects of immune tolerance and the balance of immunity in pregnancy in terms of the role of the human leucocyte antigen, placental trophoblasts, maternal immunosuppression, immune cells, cytokines and immunoregulatory molecules at the feto-maternal interface

La infección por Trypanosoma cruzi en ratones gestantes induce una respuesta inmune celular con producción de citocinas en sus fetos / Trypanosoma cruzi infection in pregnant mice induces a cellular immune response with citokines production in their fetuses

El objetivo del presente estudio fue detectar las citocinas IFN-g, IL-4 e IL-10 expresadas por células T CD4+ en tejidos de fetos de ratones con infección chagásica aguda. Para ello, se examinaron fetos de ratones NMRI cuyas madres fueron infectadas con 22×10³ tripomastigotes metacíclicos de la cepa M/HOM/BRA/53/Y de T. cruzi y preñadas durante la fase aguda de la infección. Para la detección y localización de infiltrados inflamatorios, nidos de parásitos, antígenos de T. cruzi y citocinas se emplearon las técnicas de hematoxilina-eosina, peroxidasa-anti-peroxidasa e inmunofluorescencia indirecta. Se detectaron infiltrados inflamatorios y antígenos con nidos de amastigotes en el músculo esquelético fetal. Células T CD4+ productoras de IFN-g así como depósitos de IFN-g e IL-10 fueron detectados en las secciones de placenta, corazón y músculo esquelético de fetos de ratones infectadas, mientras que células CD4+/IL-10+ se encontraron sólo en músculo esquelético, adicionalmente se detectaron depósitos de IL-4 sólo en placentas de ratones sanas. Estos resultados indican que el feto es capaz de generar una respuesta inmune propia frente a antígenos transmitidos por su madre, lo cual induce la secreción de citocinas que actuando en sinergia con los anticuerpos maternos le confieren un estado de protección contra la infección, y que la transmisión del parásito depende de factores específicos de cada madre, la cual puede modificar su capacidad de controlar tal transmisión ya sea a nivel placentario o sistémico.

The objective of this study was to detect the cytokines IFN-g, IL-4 and IL-10 expressed by CD4+ T cells in tissues of fetal mice with acute chagasic infection. For this, we examined the fetuses of NMRI mice whose mothers were infected with 22×10³ metacyclic trypomastigotes of the M/HOM/BRA/53/Y strain of T. cruzi and made pregnant during the acute phase of infection. For the detection and localization of inflammatory infiltrates, nest parasites, antigens of T. cruzi and cytokines we used hematoxylin-eosin techniques, peroxidase-anti-peroxidase and immunofluorescence. The immunohistochemical study revealed the presence of inflammatory infiltrates and antigens with amastigote nests in fetal skeletal muscle. CD4 + T cells producing IFN-g, as well as deposits of IFN-g and IL-10, were detected in sections of placenta, heart and skeletal muscle of fetuses of mice infected, while CD4+/IL-10+ was found only in skeletal muscle; in addition, deposits of IL-4 were detected only in placentas of healthy mice. These results indicate that fetuses are capable of generating their own immune response to antigens transmitted by their mother, which induces the secretion of cytokines and that, acting in synergy with the maternal antibodies, confer them a state of protection against infection; and that the transmission of the parasite depends on factors specific to each mother, which may modify its ability to control such transmission at the placental or systemic levels.

Avances en inmunidad gestacional / Advances in gestational immunity

El inicio y establecimiento de la gestación en los mamíferos dependen de la adaptación del sistema inmunológico de la madre para tolerar un feto semi-alogénico. La gestación en sí misma constituye un acontecimiento de equilibrio inmunológico, ya que mientras el sistema inmune mantiene la competencia para la defensa contra antígenos foráneos, mecanismos de tolerancia local y periférica previenen una respuesta inapropiada contra alo-antígenos fetales de origen paterno lo que pudiera provocar el rechazo del feto. La interacción materno-fetal es extremadamente compleja y es difícil determinar todos los componentes del sistema inmune involucrados. Hasta ahora se ha demostrado la participación activa de las células T y sus productos, las citoquinas y también se ha involucrado a las moléculas del complejo mayor de histocompatibilidad, los antígenos paternos y algunos inmunomoduladores como progesterona, indoleamina 2,3-dioxigeneasa y glicodelina, entre otros. Todos estos elementos parecen confluir para producir un gran cambio sistémico en el sistema inmune materno, promoviendo por una parte la tolerancia materno-fetal, crucial para finalmente permitir una gestación exitosa y, por otro lado, manteniendo una activa vigilancia inmune contra las infecciones que pondrían en riesgo la gestación y sobrevivencia de diversas especies. Se revisó la literatura más reciente acerca de los diferentes componentes del sistema inmune que han demostrado ser clave en el inicio y mantención de la gestación en mamíferos.

The initiation and establishment of pregnancy in mammals depends on the adaptation from maternal immune system to tolerate a semi-allogeneic fetus. Pregnancy itself constitutes an event of immune balance because, while the immune system maintains the capacity for defense against foreign antigens, mechanisms of local and peripheral tolerance may prevent an inappropriate response against fetal alloantigens of paternal origin which could lead to rejection of the fetus. The maternal-fetal immune interaction is extremely complex and it has therefore been difficult to identify all the immune components involved. So far, it is known that the active participation of T cells and their products, cytokines, and has also involved molecules from the major histocompatibility complex, other paternal antigens and some immunomodulators molecules such as progesterone, glycodelin and indoleamine 2,3-dioxigenase among others. All these elements seem to converge to produce a major systemic change in the maternal immune system, promoting on one hand the maternal-fetal tolerance, crucial to allow a successful pregnancy and on the other hand, maintaining an active immune surveillance against infections that might endanger pregnancy and survival of diverses species. A review of recent literature about the different components of the immune system that have proven key in the beginning and maintenance of pregnancy in mammals.

Association between maternal-fetal genetic histocompatibility and maternal undernutrition in mice: influence on intrauterine growth

OBJETIVO: Avaliar os efeitos da histocompatibilidade genética materno-fetal e sua associação com a desnutrição materna em relação ao crescimento fetal e número de fetos. MÉTODOS: Fetos singênicos ou alogênicos em relação às respectivas mães foram obtidos através de cruzamentos de camundongos com linhagens genéticas bem definidas (A/J e Balb/c). As fêmeas grávidas foram alimentadas ad libitum com dieta normal contendo 22% de proteínas ou dieta com restrição, contendo 14% de proteína e aporte máximo de 70% do total consumido pelo grupo em dieta livre. No final da gestação, o número de unidades feto-placentárias e de perdas fetais, o peso da placenta e do feto, assim como o peso do cérebro e do fígado foram anotados. RESULTADOS: Os fetos das mães submetidas à desnutrição mostraram redução no peso corpóreo, placentário e cerebral (p<0.01), sendo que a associação entre a compatibilidade genética materno-fetal resultou em maior restrição ao crescimento fetal (p<0.01). Foi observada uma redução no número de fetos viáveis por fêmea entre os animais do grupo de restrição nutricional (p<0.01). Embora a ocorrência de compatibilidade genética materno-fetal tenha resultado na redução do número de fetos viáveis e numa tendência ao aumento de perdas fetais, esta diferença não foi significante. CONCLUSÕES: Em camundongos, a ocorrência de histocompatibilidade genética materno-fetal não modificou o crescimento fetal; a desnutrição materna durante a gestação resultou em retardo de crescimento fetal com menor tamanho da ninhada, e a associação dos dois fatores aumentou a redução do peso fetal.

Particularidades imunológicas do pré-termo extremo: um desafio para a prevenção da sepse hospitalar / Immunological peculiarities of extremely preterm infants: a challenge for the prevention of nosocomial sepsis

OBJETIVO: Realizar revisão sobre os principais aspectos do desenvolvimento imunológico fetal, salientando a defesa de prematuros extremos contra patógenos bacterianos e descrevendo a situação atual de intervenções imunoterapêuticas para a prevenção de sepse hospitalar. FONTES DOS DADOS: Obtiveram-se, por meio de busca eletrônica, no banco de dados MEDLINE, artigos publicados nos últimos 15 anos referentes ao tema, e foram selecionados aqueles que trouxessem informações relevantes. SíNTESE DOS DADOS: A imunidade de prematuros extremos é deficiente devido à fragilidade da pele, à carência dos produtos de ativação do sistema complemento, ao menor pool de reserva de precursores de neutrófilos na medula óssea e à quimiotaxia, aderência, deformabilidade e atividade enzimática neutrofílicas reduzidas. Limitações adicionais são detectadas na citotoxicidade de células NK, na proliferação e produção de citocinas dos linfócitos T, na cooperação entre células T e B e na síntese de anticorpos pelos linfócitos B. Ainda não foram demonstrados benefícios definitivos de intervenções para incremento da função imunológica dessas crianças, tais como o uso de imunoglobulinas endovenosas e de fatores estimuladores de colônias mielóides. CONCLUSAO: Em conseqüência à imaturidade de diversos componentes da imunidade, prematuros extremos são altamente suscetíveis a infecções nosocomiais. As possibilidades ainda muito limitadas para a intervenção nesse sistema fazem com que o controle dos fatores extrínsecos sejam essenciais para a prevenção da sepse nosocomial nessas crianças.

Los fectos humanos estan capaces de generar una respuesta inmune T CD8 similar a la de los adultos / The human fetuses are be able to develep an adult-like immune CD8 T-cell response

Fetal/Neonatal immune responses are generally considered to be immature and weaker than in adults. We have sudied the cord blood T-cells of newborns congenitally-infected whith Tripanosoma cruzi, the protozoan agent of Chagas' disease. Our data demonstrate a predominant activation of CD8 T-cells expressing activation markers and armed to mediate effector functions. Indeed, we have detected parasite-specific CD8 T-cells secreting interferon-ã. Such response is enchanced in the presence of rIL-15. These findings point out that the fetal immune system is more competent than previously appreciated, since fetuses exposed to live pathogens are able to develop an adult-like immune CD8 T-cell response.

In utero hematopoietic stem cell therapy

In utero hematopoietic stem cell transplantation (IUHSCTx) is a promising approach for the treatment of a potentially large number of fetuses affected by congenital hematologic disorders. With technical advances in prenatal diagnosis and fetal intervention, the majority of these diseases can now be diagnosed early in gestation, allowing consideration of prenatal treatment. It, therefore, stands to reason that there is increasing interest in performing in utero hematopoietic stem cell transplantation at many centers around the world. Although the approach remains experimentally promising, expansion of clinical application will depend on improved understanding of the biological barriers to engraftment in the fetus as well as on the development of effective clinical strategies based on the hematopoietic biology of individual disorders.

Imunidade do feto e do recem-nascido / Immunity of the fetus and the newborn infant

O conhecimento da imunidade do feto e do recem-nascido e de grande importancia, por estar diretamente relacionado com a susceptibilidade deste, frente a processos infecciosos. Apresentamos uma revisao da literatura focalizando a imunidade humoral, celular, o sistema complemento e a atividade das celulas fagocitarias, chamando atencao para os aspectos mais importantes que poderao ser uteis na escolha de uma terapeutica imunologica adequada

Avaliaçäo da resposta imune materna e fetal de ratas diabéticas / Maternal and fetal immune response in diabetics rats

O objetivo deste trabalho foi estudar a resposta imunológica de ratas diabéticas, submetidas a prenhez. Utilizamos 80 ratas wistar, adultas, virgens, que foram sorteadas para compor os grupos: prenhe e nao prenhe com e sem aloxana. As ratas que receberam aloxana foram separadas de acordo com a glicemia do primeiro dia de prenhez em três subgrupos: sensibilizado (glicemia menor que 120 mg/dl), diábetes moderado (glicemia entre 120 e 199 mg/dl) e diabetes grave (glicemia maior que 200 mg/dl). Avaliou-se nestes grupos: a produçao de anticorpos maternos contra eritrócito de carneiro (SE); a transferência destes anticorpos para os filhotes; a imunidade celular materna e fetal através da técnica de produçao do fator inibidor da migraçao de leucócitos (LIF) e a atividade efetora das células NK materna. Na prenhez de ratas normais nao houve alteraçao de nenhum dos parâmetros imunológicos estudados. As ratas diabéticas apresentaram menor produçao de LIF, indicando supressao na resposta celular, que se refletiu na menor produçao de anticorpos. O diabetes associado à prenhez, além de alterar a resposta imune celular e humoral, aumentou a atividade das células NK nos grupos sensibilizado e diabetes moderado. A hiperglicemia materna suprimiu a resposta celular dos filhotes, com menor produçao do LIF. A deficiência nos níveis de anticorpos dos filhotes decorre da baixa produçao de IgG materna, única classe de anticorpos capaz de ser transferida passivamente através da placenta.

Differential expression of leukocyte common antigen in human fetal lymphoid organs

To investigate the differential expression of various types of leukocyte common antigen (LCA) isoforms during development, we analyzed human fetal lymphoid organs, including the thymus, liver, spleen, and bone marrow from 14 weeks to 29 weeks of gestational age by immunohistochemical and flow cytometric methods. In fetal thymus, over 90% of thymocytes throughout the entire fetal life expressed CD45RO and CD45RB, while CD45RA was expressed only in less than 5% of thymocytes. This expression pattern of LCA isoforms was established by a gestational age of 14 weeks or earlier, and persisted throughout the fetal period. The tissue distribution was different from each isoform; CD45RO-positive thymocytes were found in both the cortex and medulla at the 14th week with low intensity, but was localized in the cortex with increasing fetal age. CD45RB-positive thymocytes distributed mainly in the medulla from early gestational age. Among extrathymic lymphoid organs, a small portion of lymphoid cells expressing leukocyte common antigens appeared first in the liver at 10-12 weeks of gestational age and was followed by a small number in the spleen and bone marrow by 13-15 weeks. All lymphoid cells in these extrathymic lymphoid organs at this stage were CD19+ B cells. The number of these CD19+ cells increased abruptly during the early period of mid-gestational age. The pattern of tissue distribution of each LCA isoform in the fetal liver and spleen correlated well with the patterns of quantitative analysis by flow cytometry. In summary we found that different LCA isoforms expressed in cell-type-specific pattern and showed different tissue distribution during the period of fetal development, and that LCA was the earliest antigen expressed by lymphocytes in the thymus and extrathymic lymphoid organs in our series.

Sistema inmune e inmunoterapia en el recién nacido I: El recién nacido como hospedero inmunocomprometido / Immune system and immunoteraphy in the newborn I newborn as a immunocompromises host

A pesar de grandes avences para el apoyo del recién nacido grave, incluyendo la introducción de surfacteante, nuevos y más potentes antibióticos, mejores ventiladores, etc., la mortalidad asociada a sepsis continua siendo muy alta. Esto puede ser debido a la inexperiencia e inmadurez del sistema inmunológico del recién nacido. En esta primera parte se resumen los aspectos de la inmunidad, no específica (PMN), específica (células B y T) y mixta (monocitos/macrófagos, células NK), que señalan al recién nacido como un hospedero inmunocomprometido. También se hacen algunas consideraciones con respecto a otras condiciones que hacen al neonato susceptible a infecciones

The foetal immune response to maternal tetanus toxoid immunization.

Paired maternal and cord blood samples were collected at delivery from 150 women who received varying doses of tetanus toxoid during pregnancy. Tetanus specific IgM and IgG antibodies were measured in them by standard ELISA with a sensitivity for IgM of 0.001 mg/ml, and for IgG of 0.0003 IU/ml. In 22 infants an additional estimation of tetanus antibody was made 1 month after birth. The presence of specific IgM in 78% of cord samples established an active foetal immune response. The titre did not alter significantly with the number of TT doses given to the mother. Foetal IgM rose in 60% of cases at one month of age compared to cord blood levels. At this time IgG levels were uniformly diminished in accord with a maternally derived passively transferred antibody. No switch of foetal IgM to IgG production was evident. The foetal immune response thus did not confer active protection against tetanus.

Maternal fetal immunological relationship particularly mycobacterial immunity.

Thirty-nine paired maternal and cord blood from normal full term deliveries were tested for lymphocyte function by proliferative response to mitogens-Phytohemagglutinin-P (PHA) and Poke week mitogens (PWM). Monocyte function was assessed by the ability of the monocytes to release hydrogen peroxide (H2O2) in response to standard stimulus (PMA). Mycobacterial immunity was assessed by lymphocyte proliferative response to purified proteins derivative (PPD) and IgM and IgG antibody response to H37Rv and 5 atypical mycobacteria. Lymphocyte functions were significantly lower in cord blood (PHA 20.6, PWM 21.2) as compared with maternal blood (PHA 65.8, PWM 37.8). The capacity of fetal monocytes to release H2O2 was comparable to maternal monocytes. The mean proliferative response of fetal lymphocytes to tubercular protein (PPD) was 0.67 as compared (P less than 0.01) to maternal lymphocytes (3.79). Nearly 86% of the cord blood did not show any response to PPD. None of the cord blood showed IgM antibody response to H37Rv nor to any of the range of 5 atypical mycobacteria though maternal IgM and IgG response was present. There was only passive transfer of IgG antibody from mother to fetus. Hence, though this is a highly endemic area for atypical mycobacteria and M. tuberculosis, there was apparently no transplacental transfer of antigen in normal sensitized mothers.