Christopher T. Cordle

Effect of Dietary Ribonucleotides on Infant Immune Status. Part 1: Humoral Responses

The objective of this study was to further explore previously identified effects of supplemental ribonucleotides on infant immune status as measured by antibody responses to routine infant immunizations. Infants were randomized to a milk-based formula with (FN, n = 138) or without (F, n = 147) 72 mg ribonucleotides/L. A cohort of human milk–fed (HMF, n = 192) infants was also followed. Subjects were given Haemophilus influenzae type b (Hib), diphtheria tetanus acellular pertussis, and oral poliovirus vaccinations at 2, 4, and 6 mo of age, and specific antibody responses were assessed at 2, 6, 7, and 12 mo. Growth and safety data were also monitored. Using a two-group repeated measures analysis (RMA), FN-fed infants had significantly higher poliovirus type 1 neutralizing antibody (PV-VN1) responses than F-fed infants (p = 0.045). Using three-group RMA, PV-VN1 responses in HMF infants were not different from FN-fed infants, while HMF-fed infant PV-VN1 responses were significantly higher than F-fed infants at 6 (p = 0.0004) and 12 mo (p = 0.0001). FN-fed infants had responses to Hib Farr, diphtheria, tetanus toxoid, oral poliovirus–specific IgA, and PV-VN3 not significantly different from those of F and HMF infants. Growth, gastrointestinal tolerance, and adverse events were equivalent among the three groups. The FN-associated increase in PV-VN1 response and nonstatistically significant trends toward increased Hib and diphtheria antibody responses were consistent with observations from earlier studies, indicating immune benefits of nucleotide supplementation of infant formula.

Immune status of infants fed soy-based formulas with or without added nucleotides for 1 year: part 1: vaccine responses, and morbidity.

Background Immunologic development of soy-fed infants has not been extensively studied. Early studies of soy flour–based formulas showed decreased immunoglobulin production when soy protein intake was limited. However, there were no significant differences in rotavirus vaccine responses between breast-fed and soy protein isolate–based formula-fed infants. Nucleotides added to milk-based formula benefit infant immune status, but reports of the immunologic effects of adding nucleotides to soy-based formula are not available. This study evaluated immune status and morbidity of infants fed soy protein isolate formulas with and without added nucleotides for 1 year. Methods Newborn, term infants enrolled in a masked 12-month feeding trial were assigned randomly to groups fed soy formula with or without added nucleotides (n = 94, n = 92). A nonrandomized human milk/formula cohort (n = 81) was concurrently enrolled. Recommended immunizations were administered at 2, 4, and 6 months. Immune status was determined from antibody responses to Haemophilus influenzae type b, tetanus, diphtheria, and poliovirus vaccines at 6, 7, and 12 months. Parents and physicians reported morbidity data. Results All vaccine responses were within normal ranges. No response differences were observed between infants fed soy formula and those fed nucleotide-supplemented soy. However, antibody to H. influenzae type b at 7 and 12 months was higher in infants fed nucleotide-supplemented soy than in infants fed human milk/formula (P = 0.007, P = 0.008, respectively). Human milk/formula-fed infants had higher poliovirus neutralizing antibody at 12 months than did soy-fed infants (P = 0.016). Morbidity analyses showed that only physician-reported diarrhea was different among groups (groups fed human milk/formula had less diarrhea than did soy groups, P = 0.011). Conclusions Term infants fed soy protein isolate–based formulas have normal immune development as measured by antibody responses to childhood immunizations.

Immune status of infants fed soy-based formulas with or without added nucleotides for 1 year: part 2: immune cell populations.

Background Infants fed a soy protein isolate–based formula have immunization responses similar to breast-fed infants. However, cellular aspects of the immunologic development of soy-fed infants have not been studied extensively. Nucleotides added to milk-based formula benefit infant immune status, but reports of the immunologic effects of adding nucleotides to soy-based formula are not available. This study examines immune cell populations of infants fed soy protein isolate formulas with and without added nucleotides for 1 year. Methods Newborn, term infants studied in a masked 12-month feeding trial were assigned randomly to soy formula groups with and without added nucleotides (n = 94, n = 92). A nonrandomized human milk/formula-fed cohort (n = 81), was concurrently enrolled. Blood samples were collected at 6, 7, and 12 months. Thirty-two immune cell populations were characterized using three-color flow cytometry. Cellular markers were chosen to assess general pediatric immune status, emphasizing maturation and activation of B, T, and NK lymphocytes. Results All cell populations, number and percentages, were within age-related normal ranges. The only significant difference found between soy formula and human milk/formula-fed infants was the percentage of CD57+ NK T cells at 12 months (human milk/formula > soy formula, P = 0.034). There were significant differences at some time points between human milk/formula-fed and nucleotide-supplemented soy formula–fed infants in populations of lymphocytes, eosinophils, total T, helper T, naive helper, memory/effector helper, CD57−T, and CD11b+CD8+NK cells. None of the cell populations differed between infants fed soy formula versus soy plus nucleotides. Conclusions Infants fed this commercial soy formula demonstrated immune cell status similar to human milk/formula-fed infants, consistent with normal immune system development. The addition of nucleotides to soy formula did not significantly change specific individual immune cell populations but tended to increase numbers and percentages of T cells and decreased numbers and percentages of NK cells.

Effect of dietary ribonucleotides on infant immune status. Part 2: Immune cell development.

The objective of this study was to determine whether dietary ribonucleotides alter immune cell phenotypes or function in the first year of life. Newborn term infants in a double-blind, 12-mo, multicenter trial were randomized to cow milk formula groups with (FN, n = 138) or without (F, n = 147) 72 mg/L supplemental ribonucleotides. A nonrandomized HMF cohort (n = 192) was concurrently enrolled. Eighty-eight immune blood cell types were characterized by flow cytometry. Data were analyzed by multivariate ANOVA (MANOVA), ANOVA, and repeated measures analysis (RMA), with adjustments made for multiple comparisons. Ribonucleotide feeding changed subpopulations of T and natural killer (NK) cells. FN had higher numbers and percentages of memory/effector (M/E) cytotoxic/suppressor (CD45R0+CD8+, RMA) T, Fas+ M/E (CD45R0+CD95+CD3+, 6 mo) T, and CD56+CD16− NK cells (CD56+CD16−CD3−CD8−, 12 mo), and higher percentages of M/E helper (CD45R0+CD4+, RMA) T, Tc1 (IFNγ+CD4−CD3+, RMA), total interferon (IFN)γT (IFNγ+CD4+/−CD3+, RMA), Th2 (IL-4+CD4+CD3+, 7 mo), and CD57+ NK-T cells (CD57+CD56−CD3+, 6 mo, 7 mo) compared with F. Percentages of naive helper T (CD45RA+CD4+, 12 mo) and numbers and percentages of CD56+ NK-T cells (CD56+CD16−CD3+CD8−, 2 mo, 6 mo) were lower in FN than F. Percentages of M/E cytotoxic/suppressor, Th2, and CD56+CD16− NK cells in FN were significantly higher than F but were not different from HMF, whereas F was significantly lower than HMF. Ribonucleotide supplementation of infant formula supported increased T-cell maturation and affected immunoregulatory NK cell subsets. These FN-associated immune cell profiles either did not differ from those infants fed HMF or tended to be more like those fed HMF than those fed F.

Immunogenicity Evaluation of Protein Hydrolysates for Hypoallergenic Infant Formulae

Summary: Casein and soy protein were enzymatically hydrolyzed for potential use in a hypoallergenic infant formula. To assess the relative immunoreactivity of the hydrolysates, rabbits were immunized with either the intact proteins or the protein hydrolysates using a vigorous immunization protocol. Serum samples were tested using ELISA methods that quantitated IgG antibody specific for the immunizing protein hydrolysates and the corresponding intact proteins. The results showed that the protein hydrolysates had substantially lower immunogenicity than the parent proteins. Also, antibody specific for the parent protein showed very low cross-reactivity with the hydrolysates. Both of the protein hydrolysates seem to be promising candidates for use in hypoallergenic infant feeding systems.

Protein hydrolysates as special nutritional ingredients

Publisher Summary The use of hydrolyzed proteins as food ingredients dates back to the late 19th century, beginning in Europe and the Far East. These hydrolyzed proteins, which were produced by acid or enzymatic hydrolysis of vegetable and animal proteins, were used for flavoring purposes in bouillon, soups, and sauces, and they gained rapid consumer acceptance. It was only in the late 1930s and early 1940s that a parenteral grade of protein hydrolysate made by pancreatic enzyme digestion of casein was used for parenteral feeding. The discovery in the 1950s that careful charcoal treatment of casein hydrolysate could remove most of the aromatic amino acids (phenylalanine, tyrosine, and tryptophan) brought about the development of special formula for the dietary management of infants who suffer from phenylketonuria or tyrosinosis. Since then, protein hydrolysates have been widely used as the nitrogen source for the interal feeding of individuals who have specific nutritional and physiological needs. These include patients with impaired gastrointestinal function (e.g., Crohns disease), short bowel syndrome, or specific organ disease (e.g., pancreatitis, renal and hepatic). Protein hydrolysates have also found application in sports nutrition, weight control diets, and nutritional supplements. More recently, protein hydrolysates have been used in dietetic products designed for the nutritional management of cancer patients and individuals with AIDS. However, the widest use of protein hydrolysates as nutritional ingredients has been for feeding infants with intact protein hypersensitivity. The use of protein hydrolysates in these products is based on the premise that predigested proteins, when fed as amino acids and peptides, provide essential nitrogen in a non-antigenic, easily absorbed form.

Passive Immune Protection from Diarrhea Caused by Rotavirus or E. Coli: An Animal Model to Demonstrate and Quantitate Efficacy

Several studies have described the use of orally administered passive antibodies from heterologous species origin to control enteric disease caused by bacteria1–4, viruses5–13, and protozoa14. Both the therapeutic and prophylactic properties of passive antibodies have been evaluated. The therapeutic efficacy has been confined to suppressed pathogen shedding with limited effects reported on the acute clinical disease2,12. The reported lack of therapeutic effect on the course of the Escherichia coli and rotavirus diarrhea episodes may be attributed to the self-limiting nature of these diarrheas in healthy patients. Passive antibody is effective in treating Cryptosporidium infection14 and may also be effective in treating chronic diarrhea in immunocompromised patients.