Cord blood and breast-milk antibodies in neonatal rotavirus infection

Rotaviruses: immunological determinants of protection against infection and disease

Although studies of rotavirus immunity in experimental animals and humans have often yielded conflicting data, a preponderance of evidence supports the following answers to the questions initially posed. 1. What is the importance of virus serotype in formulating an optimal vaccine? Both vp4 and vp7 induce virus-neutralizing antibodies after either natural infection or immunization; the capacity of vp4 to induce rotavirus-specific neutralizing antibodies is probably greater than that of vp7. However, protection against disease after immunization of infants and young children is induced by strains heterotypic to the challenge virus (e.g., immunization with WC3 induces protection against disease induced by serotypically distinct human G1 strains). In addition, oral inoculation of infants with primate or bovine reassortant rotaviruses containing genes that encode human vp7 has not consistently induced a higher level of protection against challenge than that induced by parent animal rotaviruses (see Table I). Therefore, although vp4 or vp7 or both are probably important in inducing protection against challenge, it has not been clearly demonstrated that inclusion of the epidemiologically important human (as distinct from animal) P or G type is important in protection against human disease. 2. Which immunological effector arm most likely protects against rotavirus disease? No immunological effector arm clearly explains protection against heterotypic challenge. Protection against disease is not predicted by rotavirus-specific neutralizing antibodies in serum. Rotavirus-specific, binding sIgA in feces [detected by enzyme-linked immunosorbent assay (ELISA)] induced after natural infection does correlate with protection against disease induced by subsequent infection. However, protection after immunization with WC3 may occur in the absence of a detectable fecal sIgA response. The relationship between rotavirus-binding sIgA and sIgA-mediated neutralizing activity directed against the challenge virus remains to be determined. Binding rotavirus-specific sIgA in feces detected by ELISA may only be a correlate of other events occurring at the intestinal mucosal surface. The presence of broadly cross-reactive, rotavirus-specific CTLs at the intestinal mucosal surface of mice acutely after infection is intriguing. It would be of interest to determine the degree to which the presence of cross-reactive, rotavirus-specific CTLs in the circulation is predictive of the presence of virus-specific CTLs among intestinal lymphocytes and protection against challenge. Unfortunately, studies of virus-specific CTLs are difficult to perform in children. 3. By what means is virus antigen best presented to the host to elicit a protective immune response? Oral inoculation may not be necessary to induce a protective, virus-specific immune response at the intestinal mucosal surface.(ABSTRACT TRUNCATED AT 400 WORDS)

Antibodies to seven rotavirus serotypes in cord sera, maternal sera, and colostrum of German women

Forty percent of colostrum samples from German women showed neutralizing antibody titers of greater than or equal to 50 to rotavirus (RV) serotypes 1, 3, 4, and 6. Antibody to serotypes 2, 8, and 9 was less prevalent. Titers are, however, too low to indicate an important effect of colostrum on the RV vaccine take rate. On the other hand, about 50% of the cord serum samples showed high neutralizing-antibody titers to serotypes 1, 3, and 4, which could interfere with the take rate of RV vaccines based on these serotypes in very young infants.

[Rotavirus neonatal diarrhea]

A retrospective survey was performed among 24 neonatal care units. In the years 1989-1990, outbreaks of rotavirus infections were observed in 58 % and recurred in 46 % of neonatal care units. Six units presented with 3 or more outbreaks. Rapid diagnosis methods always were available and were usually agglutination latex test or ELISA test. Measures were suggested to limit the spread of the outbreaks : wearing of a gown ascribed to each infant (20/0) ; isolation of infected neonates (16/3) ; cohorting infected neonates (11/7) ; systematic stool examination for rotavirus identification in all neonates (9/10) ; use of gloves for handling contaminated stools (6/13). Stopping admissions and systematic stools examination in staff members were never applied.

Circulating and breast-milk anti-rotaviral antibodies and neonatal rotavirus infections: a maternal-neonatal study

In view of the high prevalence of rotavirus (RV) diarrhoea in Indian (Asian) infants in South Africa, a hospital-based study of 124 mothers and their neonates was carried out to establish the prevalence of maternal and neonatal circulating anti-RV antibodies, RV antibodies in breast-milk, and neonatal RV infections in this population. Thirty-four per cent of the mothers and 38% of the neonates had complement-fixing (CF) serum antibodies. There was a significant correlation between maternal and cord blood antibody levels (p less than 0.001; chi-square test). Fifteen per cent of hospital-born newborns showed asymptomatic RV excretion while still in hospital, mostly at 2-6 days of age, but some even earlier, with two shedding the virus before the age of 24 h. This excretion occurred in both seronegative and seropositive babies. The breast-milk of only 3.2% of the mothers was positive for CF-anti-RV antibodies, implying that either these were not present in the breast-milk or that the CF-test employed was not sufficiently sensitive for detecting these antibodies in milk specimens. Eighteen (18.2%) of 99 infants followed up showed evidence of RV infection 1-7 months after birth; none was symptomatic; 12 excreted RV in the stools while 6 others seroconverted. Asymptomatic reinfection was documented in 4 of 14 babies who had been infected initially as neonates.

Longitudinal study of rotavirus infections among children from Belém, Brazil

From December 1982 to March 1986 a group of 80 children between 0 and 3 years old who lived in the peripheral area of Belém, Brazil, were followed up for episodes of diarrhoea. A total of 441 diarrhoeal episodes were recorded and 36 (8.2%) were associated with rotavirus. This agent was the only pathogen in 50% of rotavirus-related episodes of acute diarrhoea, and strains were characterized by analysis of RNA in polyacrylamide gels. Forty-one belonged to subgroup II (long pattern) and five to subgroup I. Reinfections by rotavirus were noted in 12 children involving either the same or different subgroups. Ten distinct electrophoretypes were detected in the study period and the predominant one had the '1N2L' profile. The cumulative age-specific attack rate for diarrhoea reached 2.8 by the end of the first year of life; a frequency of 2.3 episodes of diarrhoea per child per year was observed throughout the complete investigation. In comparing the age-specific attack rates for diarrhoea between breast-fed and bottle-fed children, a peak at 6 months of age was noted in the former, and at 1 month in the latter. A comparison by Fischer's exact test (P = 0.21) provided no evidence for protection against clinical rotavirus disease by maternal milk. By the same test, however (P = 0.021), we found significant evidence that early rotavirus infections were more likely to be asymptomatic and that infections after 4 months were more likely to be symptomatic. The clinical picture in children with rotavirus-related diarrhoea was more severe than in those suffering from acute diarrhoea due to another agent.

Human viral gastroenteritis

During the last 15 years, several different groups of fastidious viruses that are responsible for a large proportion of acute viral gastroenteritis cases have been discovered by the electron microscopic examination of stool specimens. This disease is one of the most prevalent and serious clinical syndromes seen around the world, especially in children. Rotaviruses, in the family Reoviridae, and fastidious fecal adenoviruses account for much of the viral gastroenteritis in infants and young children, whereas the small caliciviruses and unclassified astroviruses, and possibly enteric coronaviruses, are responsible for significantly fewer cases overall. In addition to electron microscopy, enzyme immunoassays and other rapid antigen detection systems have been developed to detect rotaviruses and fastidious fecal adenoviruses in the stool specimens of both nonhospitalized patients and those hospitalized for dehydration and electrolyte imbalance. Experimental rotavirus vaccines have also been developed, due to the prevalence and seriousness of rotavirus infection. The small, unclassified Norwalk virus and morphologically similar viruses are responsible for large and small outbreaks of acute gastroenteritis in older children, adolescents, and adults. Hospitalization of older patients infected with these viruses is usually not required, and their laboratory diagnoses have been limited primarily to research laboratories.

Protection against neonatal rotavirus infection by breast milk antibodies and trypsin inhibitors

The role of breast milk antirotavirus immunoglobulin A (IgA) and trypsin inhibitors in limiting the acquisition of rotavirus infection during the initial 5 days of life was evaluated among 42 exclusively breast-fed hospital-born infants, 22 of whom experienced rotavirus infection. The mean concentrations of antirotavirus IgA (ELISA Units) in the breast milk of mothers of the 22 rotavirus-infected neonates was 130.4 +/- 46.4; the corresponding value in 20 noninfected neonates was 384.3 +/- 328.3 (P less than 0.001). Similarly, the trypsin inhibitory capacity (mumols/mt/ml) of breast milk in the rotavirus-infected group was significantly lower (0.109 +/- 0.095) than that in the noninfected group (0.376 +/- 0.191; P less than 0.001). The trypsin inhibitory capacity of milk showed an inverse correlation with infant stool tryptic activity (P less than 0.01). Our results indicate that the acquisition of rotavirus infection during the early neonatal period depends on the concentrations of antirotavirus IgA and trypsin inhibitors in human milk and that protection is mediated by high levels of these antiviral factors.

Development of a lymphocyte transformation assay for rotavirus in whole blood and breast milk

A multivariate assay was developed for detecting lymphoproliferative responses to rotavirus in whole blood and breast milk. Detection of lymphocyte transformation in samples from healthy uninfected adults required an assay incorporating a large number of antigen and cell concentrations and several incubation periods before pulsing. In contrast, lymphoproliferation to rotavirus was observed over a wider range of these variables in blood collected from a kidney recipient nine days post-rotavirus infection. Lymphoproliferation to rotavirus was detected in 32.5% of breast milk samples tested. The magnitude of lymphoproliferation to rotavirus did not correlate with rotavirus-specific IgG ELISA antibody titres in sera or with rotavirus-specific IgA ELISA antibody titres in breast milk.

Neonatal rotavirus infection and its relation to cord blood antibodies

Among 274 neonates born at the maternity services of an urban hospital in India, 36.1% of the infants shed rotavirus in feces (as detected by ELISA) by 72 h of life. The excretion rate increased to 70.3% among the 120 infants who stayed for 5 days or more at the hospital. Diarrhoeal symptoms of mild and self-limited nature were observed only in 19.2% of the rotavirus excretors, the remaining being asymptomatic. Among the 98 infants who received supplement feeds, 49% acquired rotavirus infection as against 24.7% of the 150 exclusively breast fed infants (p less than 0.001). Viral RNA in the feces of all rota positive infants showed the same electropherotype, indicating infection from a common source. The mean percentage rotavirus inhibitory activity of cord sera in the infected and non-infected infants was 50.2 +/- 21.7 and 56.6 +/- 19.2 respectively (p greater than 0.05), suggesting that cord blood antibodies do not offer significant protection against neonatal rotavirus infection.

Rotavirus as an important cause of diarrhoea in a hospital for children in Dammam, Saudi Arabia

A major cause of morbidity and mortality among children in developing countries is acute diarrhoea and rotavirus, a reovirus-like agent, is found to be a leading causative agent. We report here the incidence of rotavirus infection among infants and young children with gastro-enteritis treated at the Children's Hospital in Dammam, Kingdom of Saudi Arabia. One hundred and fifty children, aged between 1 and 60 months, suffering from diarrhoeal illness, were selected as the study cohort; another 150 hospitalized children of the same age group, but not suffering from diarrhoea, served as controls. Sixty-two per cent of the study children complained of watery diarrhoea and 39% of vomiting; all had mild to moderate dehydration. Seventy-two per cent had fever and 30% associated respiratory illness. Worst affected were those 7-12 months old, among whom rotavirus was detected by ELISA techniques in 39.6%, compared with 7.5% of the control children of comparable age group. We could not detect any rotavirus from control children aged over 36 months, whereas approximately 15% of the study children in this age group yielded rotavirus from the stool. The second most common pathogen isolated was Shigella ssp. It was isolated from 18.7% of children under study as against 3% of the controls.

Local production of rotavirus specific IgA in breast tissue and transfer to neonates

Rotavirus specific IgA, secretory component, and IgG were measured by enzyme linked immunosorbent assay in 20 pairs of mothers and babies to estimate antibody transfer from the mother, particularly from breast milk to neonatal faeces. Colostrum contained high titres of specific IgA and secretory component, which decreased gradually. Faeces after breast feeding for three days showed detectable titres of IgA and secretory component, with further increases by seven days. There was a positive correlation between titres of secretory component in breast milk and in faeces. To clarify the mechanism of high anti-rotavirus activity in breast milk, ratios of rotavirus specific IgA in maternal serum samples to breast milk were calculated and compared with those that were herpes simplex virus specific. Significantly higher concentrations were obtained for the herpes simplex virus specific samples, indicating that anti-rotavirus IgA is selectively produced in breast tissue.

Seasonal variations in maternal serum and mammary immunity to RS virus

We have recorded the systemic and mammary/mucosal immune responses of women following natural infection with RS virus during the second and third trimesters of pregnancy. Anti-RS virus IgG antibody levels in the sera of women collected in the first trimester of pregnancy showed a bimodal distribution with high and low antibody groups. Antibody levels increased after exposure to the winter RS virus epidemic in the second trimester of pregnancy, probably as a result of infection but only for women in the low antibody group. Despite the increases, antibody levels for these women remained well below those of the high antibody group. There was no rise in mean antibody levels after exposure in the third trimester, even among women with low antibody, suggesting a degree of immunosuppression in late pregnancy. There was no evidence that infection during pregnancy was associated with adverse consequences for the infant. Exposure to RS virus in the first two trimesters, but not the third, was associated with high colostral IgA antibody levels that were maintained in the milk throughout the first 7 weeks of lactation. There was a significant correlation between colostral and maternal nasal IgA antibody levels at delivery. Levels of blood or colostral lymphocyte transformation responses at delivery were unaffected by exposure to RS virus in pregnancy. These observations upon natural infection suggest that vaccination during pregnancy is likely to achieve only marginal effects upon serum antibody levels but boost maternal mammary/mucosal immunity.

[Rotavirus reinfections in children of Belém, Pará, Brazil]

Reinfecções por rotavírus foram detectadas em 7 (9,2%) de 76 crianças habitantes da periferia de Belém, Pará, Brasil, no decurso de seus primeiros 20 meses de vida. A presença de rotavírus classificados no subgrupo II ("long pattern") foi assinalada, tanta na primeira como segunda infecções, em cinco desses indivíduos. Em duas situações, a primeira infecção foi causada por rotavírus subgrupo II e, a reinfecção, por rotavírus de subgrupo não claramente caracterizado. Seis diferentes padrões foram observados, não ocorrendo casos em que, numa única criança, se tenham assinalado perfis homólogos. O maior intervalo de tempo registrado entre duas infecções no mesmo indivíduo foi de 19 meses, enquanto que o menor, de 6. Formas sintomáticas em ambos os processos infecciosos se apresentaram em cinco crianças; em duas, os primeiros episódios revelaram-se assintomáticos, sucedendo-se quadros diarréicos. Em seis dos sete indivíduos, observaram-se soroconversões para rotavírus durante a segunda infecção; durante a primeira, entretanto, a elevação significativa nos níveis de anticorpos grupo-específicos se registrou em apenas um caso (Paciente F).

A prospective study of rotavirus infections in neonatal and maternity wards

The occurrence and symptomatology of rotavirus infections was studied at three maternity wards and one neonatal unit. Rotavirus was identified in 12.7% of 553 infants and 1.3% of 542 mothers at the maternity wards. Infections were more frequent in a mixed obstetric/gynecology ward than in the pure obstetric wards. Only 10% of the infants had symptomatic infections. Subgroups of rotavirus was determined in 41 infants: 22 of subgroup I and 19 of subgroup II, which is the subgroup accounting for the majority of childhood gastroenteritis. Rotavirus was found in faecal samples from 37% of the infants at the neonatal unit during an eight-month survey. A seasonal variation with most infections during colder months was seen. Subgroup determination was possible in 29 cases, 14 subgroup I and 15 subgroup II. Fifteen per cent of the infections demonstrated diarrheal symptoms. No significant difference among other clinical data registered was seen among rotavirus infected compared to the non-infected infants. We conclude that neonatal rotavirus infections occur as an endemic infection at our maternity wards possibly combined with infections due to external sources of virus in mixed wards and neonatal units.

Cellular reactivity to respiratory syncytial virus in human colostrum and breast milk

Colostrum and breast-milk samples were taken from 23 mothers between 2 days and 7 weeks postpartum and were examined for the presence of cellular reactivity to respiratory syncytial (RS) virus using a lymphocyte transformation assay. Positive responses were detected in nine of the 23 (39%) samples taken at 2-5 days postpartum, but this reactivity was undetectable at 3 weeks. Positive responses developed in a further three mothers during the 3-7-week period of lactation, suggesting a response to virus infection. Colostral whey was found to suppress the cellular response to RS virus and inhibition was related to the level of specific IgA antibody to RS virus present in the whey. The role of colostral cellular reactivity in protection of breast-fed infants from RS virus bronchiolitis is discussed.

Serotypic characterization of rotaviruses derived from asymptomatic human neonatal infections

Nineteen rotavirus strains derived from asymptomatic neonates (seven from England, five from Australia, two from Venezuela, and five from Sweden) were successfully cultivated in primary African green monkey kidney cell cultures, serotyped by plaque reduction neutralization tests, subgrouped by indirect enzyme-linked immunosorbent assay, and electropherotyped by polyacrylamide gel electrophoresis. All 19 strains were shown to fall into one of the four known human serotypes; serotype 1 (all Venezuelan strains), serotype 2 (all Swedish strains), serotype 3 (all Australian strains), or serotype 4 (all English strains). Hyperimmune guinea pig serum raised against the Venezuelan strain (M37) neutralized not only serotype 1 (strain Wa) but also serotype 4 (strain St. Thomas no. 3) viruses to a similar degree. The English, Australian, and Venezuelan isolates were found to belong to subgroup 2, and the Swedish strains were subgroup 1 viruses. The potential importance of these rotaviruses obtained from neonates as possible vaccine candidates is discussed.

Infection in piglets with a porcine rotavirus-like virus. Experimental inoculation and ultrastructural examination

A rotavirus-like virus has been isolated from cases of neonatal diarrhoea in piglets. No antigenic relationship with known rotaviruses or with an American strain of a rotavirus-like virus has been demonstrated. Morphologically the virus is similar to known rotaviruses, but it differs in the ability to form syncytia of the enterocytes in the small intestine.

Antimicrobial properties and microbial contaminants of breast milk--an update

A review of recent studies of antibacterial, antiviral and antiprotozoan factors in human breast milk is presented. Also reviewed are the microbial contaminants that have been detected in human milk with a particular focus on cytomegalovirus and rubella virus, both of which have recently been shown to infect infants via breast milk.

Acute diarrhoea and rotavirus infections in young children in Kuwait

The role of rotavirus infections in acute diarrhoea in young children was studied over a period of one year. Rotavirus was detected by electron microscopy and enzyme immunoassay methods in 40.2% of faecal specimens from 343 children with acute diarrhoea and in 4.7% of 86 controls. The infections were most common in children aged 2-12 months (42.3%). Twelve per cent of the rotavirus infected children were also infected with bacterial enteropathogens (Salmonellae, Shigellae and enteropathogenic Escherichia coli). The incidence of rotavirus infections was not related to sex, socio-economic or nutritional status of children. Rotavirus-associated diarrhoea differed in several clinical parameters from bacterial associated and nonspecific diarrhoea. Rotavirus was detected throughout the year but was most frequent during months with little rainfall and low humidity (March-May). Our results suggest that in Kuwait, rotavirus infection is a major cause of childhood diarrhoea.

Faecal and pharyngeal shedding of rotavirus and rotavirus IgA in children with diarrhoea

In 70 children 0-4 years of age with acute diarrhoea, the shedding of rotavirus and the excretion of rotavirus-specific IgA antibody in the stools were examined throughout the period of clinical symptoms. Quantitative detection of rotavirus and IgA was performed by an ELISA technique. The maximal rotavirus shedding was found between the second and fifth day and the maximal excretion of IgA antibody about the seventh day, which marked the clinical recovery of most children. Throat swabs were examined for both virus particles and specific IgA antibody to try to document the respiratory spread of rotavirus infection. Rotavirus antigen could not be demonstrated in the throat swabs, but specific IgA antibody was detected at levels comparable to the faecal specimens obtained at clinical recovery. The observations indicate that the presence of rotavirus secretory IgA limits the duration of diarrhoea and plays a major role in the intestinal resistance to infection.

Rotavirus shedding by newborn children

We studied the shedding of rotavirus by newborn children in the nurseries of a large maternity hospital in Caracas, Venezuela, throughout the year 1982. Sixty-two (57%) of 108 children examined shed the virus within the first few days of life. Four (6%) of the 62 children who shed rotavirus had diarrhea but only one of them required oral rehydration therapy. The rotavirus specimens were identified as subgroup 2 in an ELISA subgrouping assay that employs monoclonal antibodies. Analysis of the RNA extracted from 52 of the samples by electrophoresis revealed a similar migration pattern in all the specimens; their identity was confirmed by crosshybridization analyses which revealed a strong degree of genomic homology among the strains studied.

Epidemiology of human rotaviruses as determined by electrophoresis of genome RNA

An epidemiological survey was made of rotavirus infection in a children's hospital by determining changes in rotaviral genome patterns by means of polyacrylamide gel electrophoresis. In 180 fecal samples collected between December 1978 and June 1981, 53 distinct patterns were obtained belonging to 13 different types. Two of these patterns dominated in endemic nosocomial infections of neonates until 1981, when one of them was replaced by a third pattern. Two epidemics of diarrhea in the neonatal wards were associated with an endemic and an exogenic rotavirus strain respectively. The latter was not established as an endemic strain. Three patterns were found exclusively in isolates from infants with nosocomial infection and one pattern was found with a doubled fifth segment, suggesting a double infection. The latter findings support the conjecture that there is reassortment of rotavirus genomic segments in vivo.

Acute diarrhoea associated with rotavirus among children living in Belém, Brazil

Between January 1979 and December 1980, rotaviruses were detected in faecal samples from 122 (33.1%) of 369 diarrhoeic children less than six years old, living in Belém, Brazil. In 55 (45.1%) of the 122 rotavirus-positive specimens, no bacteria or parasite associated with gastro-enteritis was found. Salmonella typhimurium, Shigella and Escherichia coli were found in 92 (35%) of the 263 faecal specimens examined for bacterial pathogens. Rotaviruses were readily detected throughout the year, which may indicate no seasonal pattern of incidence in the Belém region. A comparison of the excretion of rotavirus was made between children of two socio-economic groups. Of 144 children from the higher level group, 63 (47.3%) excreted rotavirus, whereas only 12 (16.7%) of those from the lower level did so. Vomiting (68.0%) and fever (65.6%) were the main symptoms, other than diarrhoea, exhibited by the 122 rotavirus-positive children.

Studies on human lacteal rotavirus antibodies by immune electron microscopy

In vitro studies carried out by immune electron microscopy (IEM) indicate that rotavirus aggregation detected in the stools of newborn breast-fed infants with rotavirus infection is antibody-induced. Aggregation of rotavirus particles occurred with the IgA-containing fraction of expressed breast milk (EBM) obtained five days postpartum and with the IgA- and IgG-containing fractions of a pool of EBMs containing samples collected 2-3 days postpartum. Bovine milk fractions also demonstrated this activity in the IgG- and IgA-containing fraction. Studies on unfractionated EBMs from a mother who experienced a rotavirus infection during the 43rd week of lactation showed that following rotavirus infection all three major classes of rotavirus-specific antibodies were present in breast milk, this being confirmed by enzyme immunoassay.

Immunity to rotavirus in conventional neonatal calves

The local and systemic humoral immune responses to rotavirus were studied in six conventional neonatal calves. Attenuated bovine rotavirus was administered either orally or directly into an isolated intestinal loop. The parameters monitored were neutralizing rotavirus antibody in serum, immunofluorescent and neutralizing rotavirus antibody in intestinal loop washings, and rotavirus antibody-producing cells in intestinal mucosa. An antibody response was observed in the serum and intestinal secretions from one calf only. Viral replication was not detected in the isolated intestinal loop. Rotavirus antibody-producing cells were found in the intestinal mucosa of five calves. Double staining revealed that most of these cells produced antibody of the immunoglobulin A class. The conclusions were: (i) a previously described system to detect rotavirus antibody-producing cells can be used to study immune responses in neonatal calves, (ii) the class or subclass of antibody in rotavirus antibody-producing cells can be determined by double immunofluorescent staining, (iii) neonatal calves respond to rotavirus inoculation with a local immunoglobulin A response, and (iv) most of the rotavirus antibody-producing cells are located in the mucosa of the proximal small intestine.

Virus-infected colostral cell cytokine stimulation of human leukocyte natural killer cytotoxicity

Natural killer cytotoxicity is an important antiviral defense mechanism. Human peripheral blood mononuclear cells cultured with herpes simplex virus (HSV)-infected cells produced a cytokine. This substance stimulated adult natural killer cytotoxicity from 53.0 +/- 10.5% to 79.8% (P less than 0.01) against HSV-infected target cells. These data resulted in a calculated cytokine-dependent cellular cytotoxicity (CDCC) value of 65.8%. Cytokine production was not stimulated by uninfected cells and was independent of the presence or absence of antibodies to HSV in sera of donors and mononuclear cells. Cells from human colostrum also produced an HSV-stimulated cytokine which mediated CDCC by using both adult (19.8 +/- 3.9%) and neonatal (18.6 +/- 3.4%) mononuclear effectors cells. Colostral cell cytokine production was also independent of donor HSV serology. Not all colostral cultures produced the cytokine, and in general colostrum-stimulated CDCC was lower than peripheral blood leukocyte-stimulated CDCC. Colostral cell cytokine stimulation of neonatal natural killer cytotoxicity may account in part for the increased nonspecific resistance of breast-fed infants to viral infection.

Neonatal rotavirus infection: role of lacteal neutralising alpha1-anti-trypsin and nonimmunoglobulin antiviral activity in protection

Expressed breast milks (EBMs) were collected from mothers of rotavirus (RV)-excreting babies and from mothers whose babies were RV free during an outbreak of asymptomatic RV infection in a newborn nursery to determine the role of lacteal anti-RV neutralising activity, alpha1-anti-trypsin activity, and nonimmunoglobulin antiviral factor in protection of neonates from RV infection, and although all of the above factors were present in the majority of the EBMs, no correlation could be found between their presence in EBM and protection from RV infection. A significant rise in both neutralising activity and subgroup 2 antibodies, was demonstrated in the EBM of one mother who experienced a subgroup 2 RV-associated diarrhoea during lactation. However, the alpha1-anti-trypsin activity and the nonimmunoglobulin antiviral levels remained the same. The importance of these factors in passive immunity with reference to virus dose is discussed.

Enhancement of human rotavirus infectivity in a monkey kidney cell line by human expressed breast milk

Eight of forty (20%) human expressed breast milks enhanced the infectivity of human rotavirus (HRV) when assayed by immunofluorescence in a monkey kidney cell line (LLC-MK2). This enhancement was demonstrated with two HRV strains, one derived from a fecal specimen of a child with acute gastroenteritis, the other a tissue culture adapted strain. The phenomenon could have important implications in the pathogenesis of HRV infections and in future vaccine programs.

Effect of fractions of Ethiopian And Norwegian colostrum on rotavirus and Escherichia coli heat-labile enterotoxin

Samples of colostrum from both Ethiopian and Norwegian women contained antirotavirus activities of immunoglobulin and non-immunoglobulin nature. No significant differences in rotavirus immunoglobulin A or in rotavirus-inhibiting activity were found between samples from the two countries. The non-immunoglobulin inhibitory activity was trypsin sensitive and heat stable (100 degrees C for 10 min). Escherichia coli heat-labile enterotoxin antibodies were measured in the colostrum samples by enzyme-linked immunosorbent assay. No E. coli enterotoxin-specific immunoglobulin A was detected, possibly due to the high background caused by the nonspecific adsorption of immunoglobulin A to the enzyme-linked immunosorbent assay plates in the absence of toxin. A total of 5 of 15 Ethiopian colostrum samples and 0 of 11 Norwegian colostrum samples neutralized the effect of E. coli heat-labile enterotoxin on YI adrenal cells. Both the Ethiopian and the Norwegian colostrum samples contained a non-immunoglobulin enterotoxin-inhibitory activity when the toxin was measured by enzyme-linked immunosorbent assay. This inhibitory activity was not trypsin sensitive, and extraction by chloroform-methanol indicated that the inhibitor was of a lipid nature.

Acute diarrhea and rotavirus infection in newborn babies and children in Yogyakarta, Indonesia, from June 1978 to June 1979

A longitudinal study of acute diarrhea in children in Yogyakarta, Indonesia (June 1978 to June 1979), showed little variation throughout most months of the year in numbers of children admitted to hospital and in numbers infected with rotaviruses. Both decreased during November and December coincidentally with seasonal change from dry to wet conditions. Rotavirus particles were identified by electron microscopy in fecal specimens from 126 of 334 (38%) infants and children with acute diarrhea. Nosocomial rotavirus infections occurred in 11% of control children admitted to hospital for other reasons. Socioeconomic level and preexisting nutritional status did not influence the incidence of rotavirus excretion. Rotavirus infections were most common in children aged 6 to 24 months. There was a low incidence of infection in infants less than 6 months old. Rotavirus infection was seldom observed in newborn babies delivered in an urban hospital nursery, in a rural health center, or at home. One of 72 newborn babies with diarrhea excreted rotavirus. One of 53 healthy newborn babies excreted rotavirus. It is concluded that, in Indonesia, rotavirus infection is a major cause of childhood diarrhea throughout the year, but is an uncommon cause of diarrhea in newborn babies.