It has been known for many years that neonatal rabbits are made tolerant by the feeding or injection of bovine serum albumin (BSA) (1–3). On the other hand, older (20+ days) orally immunized rabbit kits respond with anti-BSA production (4), primarily of the IgG subclass (5). Under some conditions, 20 d old kits from orally immunized dams are suppressed in their immune responses to either orally or parenterally administered BSA (4). A study of possible factors in milk that affect the responsiveness of neonates shows that anti-BSA of the IgG isotype is readily transferred into milk by the dam and subsequently is absorbed through the gut into the circulation of nursing kits (6). We now present further studies on the maternal regulation of the immune responses of rabbit kits to BSA and the factors involved.

The acquired immunodeficiency syndrome-related complex was identified in a mother and one of her nonidentical twins. Generalized lymphadenopathy was first noted in the infant at age 17 months, and that of the mother was incidentally discovered 6 months later. The father, who had had homosexual contacts before the conception of the twins, appeared to be in good health. No one in the family had constitutional symptoms or showed signs of opportunistic infection. Both parents and the patient had hypergammaglobulinemia, low T-helper-to-suppressor-cell ratio, and positive serum antibody to human immunodeficiency virus. Attempts to isolate the virus from all family members were unsuccessful. The twin brother was in good health with a normal immunologic profile and negative antibody to human immunodeficiency virus.

Rabbit dams fed 0.1% BSA for various periods before and during lactation produced anti-BSA of low avidity and IgG isotype in serum and milk. Milk anti-BSA and IgG concentrations were one-third to one-half of those in the serum. At birth, kits had IgG and anti-BSA serum concentrations approximately equal to their dams. Both fell rapidly for the first 10-20 days, levelling off at about 1 mg IgG/ml. Kits born to unimmunized dams and suckled by dams with anti-BSA in the milk showed increasing anti-BSA in serum for the first 12-16 days, falling by 20 days. Foster-suckling on immunized dams beginning at various times after birth showed antibody uptake from birth through 12 days of age. Thus immunoglobulins are among factors absorbed from milk that have potential for regulating the immune responses of rabbit neonates.

This article describes the immunologic and pulmonary abnormalities and the chemical composition of pleural effusion fluid in a patient with intestinal lymphangiectasia as they are effected by therapeutic measures during a 7-year period. Lymphedema was first noticed in the patient at 3 years of age, and pleural effusions developed 7 years later. Thoracentesis demonstrated that the right pleural fluid was yellow, clear, and had the composition of lymph. The left pleural fluid was milky and had a higher triglyceride and lymphocyte content than the right pleural fluid. Complete removal of pleural fluid transiently increased total lung capacity to a maximum of 52% predicted. Strict dietary management with a low-fat and high-protein diet resulted in a transient partial reversal of circulating lymphopenia and low T cell concentration. This was accompanied by a decrease in lymphocyte and T cell concentration in the pleural fluid. Unstimulated mononuclear cells from pleural fluid synthesized increased amounts of DNA, and added mitogens or antigens further increased DNA synthesis. Dietary therapy had a minimal effect on this DNA synthesis. Despite circulating hypogammaglobulinemia, normal antibody activity was detected. The proportion of B cells in pleural fluid was greater than that in the circulation, and dietary therapy did not alter this difference. Pulmonary physiology improved during the initial 9-month period of diet therapy, but then the rate of fluid accumulation increased, causing respiratory compromise. Stability was achieved by a right-sided pleurodesis, followed 18 months later by a left pleurodesis with the addition of a shunt to provide internal lymph drainage.

The efficacy and safety of short-term supplemental peripheral hyperalimentation (PH) was evaluated in 15 hospitalized cystic fibrosis (CF) patients who exhibited varying degrees of pulmonary disease severity and nutritional impairment. An average of 1000 supplemental calories/day were administered intravenously for a 2- to 3-week period to patients being treated with parenteral antibiotics for exacerbation of their pulmonary disease. Eleven of 15 patients responded with a weight gain of greater than 2.0 kg and showed continued weight gain and stabilized pulmonary status for the 6- to 12-month follow-up period; two patients showed dramatic reversal of poor weight gain and growth following PH. Total calorie intake (oral + PH) equaled 141 +/- 40% of the recommended dietary allowances (RDA) in responders, with 45 +/- 12% RDA contributed by PH, in contrast to 68 +/- 20% of the RDA for total calories with 31 +/- 13% supplied using PH achieved in the nonresponders. Linoleic acid deficiency was documented in these patients (linoleic acid level as a percent of total fatty acid = 21.9% +/- 1.41 SEM vs 31.8% +/- 1.16 SEM in normal controls), and all seven patients achieved normalization of linoleic acid level after PH. Prior assessment of nutritional status (anthropometric measurements) or of severity of pulmonary disease (NIH clinical score) did not allow prediction of response to PH. No complications resulted from administration of PH to these hospitalized CF patients.

Gastroesophageal reflux (GER) was initially diagnosed in two black infants, aged 5 and 9 months, as a cause of their chronic lung disease and failure to thrive. Both infants were treated with bethanechol chloride as part of the management of their GER, but respiratory failure developed in both patients and they required ventilatory support. Both infants had severe air trapping, CO2 retention, difficulty in being weaned from mechanical ventilation, and Staphylococcus aureus cultured from their respiratory tract secretions. These factors led to the suspicion of cystic fibrosis (CF), and this diagnosis was subsequently confirmed by sweat test. The condition of both infants improved substantially on withdrawal of bethanechol therapy and the institution of a regimen of CF care. The early diagnosis of GER in these infants may have led to a delay in diagnosis and treatment of CF.

The effect of feeding xenoserum (xs) on cytolytic cell activity induced by parenteral injection was examined in C3H/N mice. Spleen cells were cultured with xs and then assayed for cytolytic activity against a panel of 51Cr-labeled YAC-1, AKR-A, or P815 target cells. Prior feeding resulted in significant suppression of responses stimulated by injection and culture. The induction of these responses was antigen specific for xs whereas the effector stage represented polyclonal activation of cytolytic cells. Some effector cells were lysed by either anti-Lyt 2 or anti-NK- 1.2 and complement and some were blocked by anti-Lyt 2 or anti-T200 in the cytotoxicity assay. Thus, both cytolytic T and NK-like cells were suppressed by antigen feeding. Activity of TH cell-derived factors which enhance cytolytic activity (“promoter” factor, interferon, and interleukin 2) also was diminished in culture supematants of cells from mice fed soluble antigens. The conclusion that polyclonal cytolytic responses induced by soluble antigen can be regulated by prior enteric stimulation is made.

The effects of local antigenic exposure on the responsiveness of systemic T cells were evaluated after C3H mice were given drinking water containing 6% bovine serum albumin (BSA) for 10 days and challenged sc with 1.0 mg BSA in adjuvant 28 days after the initiation of antigen feeding. During the first 28 days, no evidence of in vitro antigen-induced proliferation [( 3H]thymidine incorporation) was detected in whole lymphocyte populations from the peripheral lymph nodes (PLN), spleen, or mesenteric nodes. In contrast, PLN cells treated with anti-Lyt-1 plus complement (C) had a significant proliferative response only if the cells were obtained during the first 6 days of antigen ingestion. Lymphoid cells from the same animals, treated with anti-Lyt-2 and C, did not respond to antigen. Two or 4 days after the injection, given on day 28, whole PLN cell populations from antigen-fed mice showed proliferation. No response was observed with PLN cells obtained 8 days after injection. Shortening the interval between the initiation of feeding and parenteral challenge partially restored proliferative responses detected 8 days after injection. Cultures prepared 4 days after simultaneous oral and parenteral antigenic exposure showed proliferation equal to or greater than cultures from mice that received only the injection. These data show that systemic T cell responsiveness is not eliminated by ingestion of soluble antigen, but rather is modulated in a manner previously detected in the humoral immune system.

Peripheral lymph node cells from C3H mice that were fed and injected with bovine serum albumin (REG cells) demonstrate an impaired proliferative response to antigenic stimulation in vitro compared to cells from mice only injected with BSA. To determine whether suppressor cells contributed to this enterically induced impairment of systemic T cell responses, REG cells were pretreated with various monoclonal antibodies and complement (C), and were then co-cultured with antigen-reactive indicator T cells (IND) from parenterally immunized mice. Proliferation of IND cells [( 3H]thymidine uptake) was suppressed only if REG cells were treated with anti-Lyt-2 and C before co-culture. The ability of anti-Lyt-1 plus anti-Lyt-2 and C treatment to abrogate suppression suggested that the suppressor effect was due to an Lyt-1+, 2- REG cell. Suppression was independent of Lyt-2+ IND cells, and was observed at different antigen concentrations, cultivation times, and cell densities. The cells responsible for suppressor activity were radiosensitive, nylon wool nonadherent, and antigen specific. These data suggest that an Lyt-1+, 2- T cell could be an important component in mediating enterically induced regulation of systemic T cell responses.

Following ingestion of bovine serum albumin (BSA), human infants and rabbits synthesize circulating anti-BSA. Using a similar protocol, the serum antibody response was examined in C3H mice offered 0.1, 1.0 or 6.0% BSA for 10 or 56 days. Sera from these animals contained similar amounts of antigen, but anti-BSA was undetectable. Half the animals in each group were subsequently injected i.v. with 50.0 mg BSA. Mice fed 1.0 or 6.0% BSA were unresponsive to this challenge, but animals fed 0.1% BSA responded comparably to i.v. immunized, non-fed controls. The remaining animals in each group were injected s.c. with 1.0 mg BSA in adjuvant. Most of these mice produced circulating anti-BSA. However, these responses were significantly reduced relative to s.c. immunized, non-fed controls. Hyporesponsiveness again was least after 0.1% BSA ingestion. CF1 mice and BN, HCR and HCS rats fed 0.1% BSA for 56 days also did not produce circulating antibodies during ingestion, and almost all were hyporesponsive after parenteral challenge. Suppression of specific antibody responses also was observed in C3H mice fed and challenged with diphtheria toxoid. The data suggest that under identical experimental conditions, ingestion of soluble protein antigens induces a state of systemic hyporesponsiveness in mice and rats in contrast to the systemic immunity demonstrated in human neonates and adult rabbits.

Postprandial levels of copper, ceruloplasmin, iron, total iron binding capacity, cholesterol, vitamin A, carotene, folic acid, vitamin C, albumin, and total globulins in plasma, of 25-OH-vitamin D in serum, and of glutathione reductase activity, an index of riboflavin status, in erythrocytes were determined in a group of 18 juvenile cystic fibrosis patients receiving specialized outpatient care with attention to diet, vitamin supplementation, and pancreatic enzyme replacement. Bone mineralization was assesed by radiographic and photon beam technique. In the plasma of cystic fibrosis patients, levels were elevated for copper, ceruloplasmin, total globins, and total proteins and were depressed for iron, vitamin D, vitamin A, carotene, and albumin. Cortical thickness was diminished in the patients, but bone density was not. For patients with cystic fibrosis, a relation was established between forced vital capacity and certain biochemical indices in plasma. As forced vital capacity decreased, plasma levels increased for copper, total globulins and total proteins and decreased for albumin.

Immune responses following antigen ingestion vary from stimulation to suppression depending on animal species, antigen, and experimental protocol. Young adult rabbits were given either 0.02% diphtheria toxoid or 0.1% bovine serum albumin in drinking water for 10-day periods, a protocol previously found to immunize human infants fed bovine serum albumin. Specific serum antibody was detected by radioimmunoassay in 10 of 13 rabbits fed diphtheria toxoid for 10 days and 11 of 13 rabbits fed bovine serum albumin. Response to oral diphtheria toxoid in some animals was equal to that after an injection of alum-precipitated diphtheria and tetanus toxoids. All rabbits fed a second course of either antigen showed an enhanced, rapid rise in antibody concentration. Avidity of the antibody also increased markedly, suggesting that priming and memory had been established during the first feeding. Similar anamnestic responses occurred in animals given a parenteral challenge after ingesting antigen. One month after administration of diphtheria toxoid, no significant difference in serum antibody levels was present between unfed animals challenged with diphtheria-tetanus toxoids and although avidity of the antitoxin was higher in fed animals. Antibody activity could be detected only in the immunoglobulin G serum fractions with either antigen. These responses suggest that oral immunization protocols using protein antigens can be adapted for use against toxins causing disease.

Employing the techniques of immunofluorescence, radioimmunoprecipitation, and radioimmunodiffusion, the development of antibody responses to RSV and BSA and the localization of immunoglobulin containing cells in the mammary glands, was studied in groups of pregnant rabbits after intravenous (IV), per oral (PO) or trans-tracheal (IT) immunization with RSV and BSA during late gestation. A predictable IgM and IgG and no IgA antibody response to RSV was observed in the serum. The secretory response to RSV was characterized by the regular appearance of IgA antibody in the colostrum and milk after IT and PO immunization but not after IV immunization. The proportion of IgA staining cells in the mammary tissues was found to be 50% higher in the animals immunized by IT or PO routes than by the IV route. No infectious virus or RSV antigen was detected in the breast. Most animals elicited IgG anti-BSA response in the serum, colostrum and milk, and a few evidenced IgA in serum. However, IgA response to BSA was notably absent in colostrum and milk. These observations suggest independent contributions of bronchus associated and gut associated lymphoid tissue to the development of mammary immunity. More importantly, significant differences exist between soluble dietary proteins and particulate viral antigens in their ability to induce breast milk antibodies.