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Biomedical subjects

N F Pierce

Publications and source records attributed to N F Pierce.

At least 37 records · Page 2Linked to original sources
PubMed1986

M cell transport of Vibrio cholerae from the intestinal lumen into Peyer's patches: a mechanism for antigen sampling and for microbial transepithelial migration.

Viable Vibrio cholerae O1 were inoculated into the intestinal lumen of nonimmune rabbits. The vibrios were phagocytosed by M cells over Peyer's patch lymphoid follicles, carried in vesicles through the epithelium, and discharged among underlying lymphocytes and macrophages. Autoradiography of V. cholerae labeled with [2-3H]adenine confirmed transport. Indigenous bacteria with and without capsules were also taken up from control loops and carried through M cells into Peyer's patches. V. cholerae killed by acidification, formalin, heat, or UV irradiation were not taken up, a result that may have relevance for development of oral vaccines. Ruthenium red stain revealed gaps in the layer of mucus over M cells, glycocalyx bridging the space between vibrios and M cell microvilli, and knobby projections over membranes of M cell microvilli; these projections were not found over absorptive cells. M cells thus convey viable enteric microbes, including V. cholerae that are not otherwise invasive, into intestinal lymphoid tissue, where mucosal immune responses are initiated. Uptake and transport by M cells may also assist certain pathogenic bacteria in traversing the mucosal barrier and initiating systemic infection.

Animals↗
PubMed1986

Disseminated Curvularia infection. Additional therapeutic and clinical considerations with evidence of medical cure.

A previously reported case of cerebral infection due to Curvularia lunata is more fully described. Medical cure was apparently achieved after 30 months' treatment with amphotericin B. Success was achieved only when the drug was given in a dose of 40 mg, three times per week, and was continued for six months after enhanced computed tomographic scans no longer showed cerebral lesions. Immunologic studies suggested the infection was accompanied by an unexplained defect in cell-mediated immunity.

Adult↗
PubMed1985

Role of cholera toxin in enteric colonization by Vibrio cholerae O1 in rabbits.

The role of cholera toxin (CT) in mucosal colonization by Vibrio cholerae O1 was studied in rabbits by using toxinogenic V. cholerae and nontoxinogenic (A-B+ or A-B-) recombinant mutants derived from them. After oral inoculation, toxinogenic strains colonized intestinal mucosa significantly more efficiently than did either A-B- or A-B+ mutants; average colonization was increased 1.5- to 30-fold with toxinogenic strains, depending on the inoculum used and the portion of intestine studied. Additionally, colonization by an A-B- mutant was increased to the levels of its toxinogenic parent by coadministration of CT with the inoculum. We conclude that CT contributes significantly to mucosal colonization by V. cholerae and that this effect is not due to an interaction of the CT B subunit with its mucosal receptor. The possibility that this effect contributes to the in vivo selection of hypertoxinogenic variants of V. cholerae is considered.

Animals↗
PubMed1985

Effect of protein deprivation on immunoregulatory cells in the rat mucosal immune response.

Secretory IgA antibody responses such as those directed against respiratory and enteric pathogens, may be impaired in protein-calorie malnutrition. In previous studies using a rat model of the mucosal immune response to cholera toxin, as little as 2 weeks of severe protein deprivation markedly impaired mucosal anti-toxin production. The present studies examined the effect of protein deprivation on lymphocyte populations which adoptively transfer either priming or suppression of a mucosal anti-toxin response from malnourished donor rats to syngeneic well nourished recipients. Either 2 or 8 weeks of protein deprivation severely impaired the development of thoracic duct lymphocytes which could transfer priming or suppression after intraduodenal priming, and impaired splenic suppressor cell development after s.c. priming. The abrogation of suppression by protein deprivation was dependent on the dose of s.c. antigen used to induce suppression. Refeeding rats after two months of protein deprivation led to recovery of both priming cell and suppressor cell function. Severe protein deprivation induces a reversible defect in both priming and suppressor cell populations; the net effect is an impaired mucosal immune response.

Animals↗
PubMed1984

From the National Institute of Allergy and Infectious Diseases. Summary of the 19th United States-Japan Joint Cholera Conference.

Classical cholera has reappeared in Asia after a 20-year hiatus, reminding us that we still have much to learn about the epidemiology of this disease. The unexpected recovery of V. cholerae from nonendemic estuarine waters suggests that the continued occurrence of clinical cholera may not be entirely dependent on repeated contamination of environmental waters by man. Of critical importance has been the discovery and partial characterization of new enterotoxins produced by V. cholerae and ETEC, a finding that further complicates the already complex problem of fully elucidating the virulence mechanism of these organisms. The recent purification of Shiga toxin is beginning to provide clues as to its structure, function, and possible pathogenic role in EPEC-related hemorrhagic colitis and diarrhea. The conversion of virulent V. cholerae into less virulent strains by genetic engineering provides hope for the ultimate development of safe and effective live oral cholera vaccines. Intestinal Peyer's patches process living and killed enteropathogens differently, and this discovery may afford insights into ways to improve antigen potency. Enterotoxins differ fundamentally in their biochemical effects, and not all of them evoke active electrolyte secretion by altering cyclic-nucleotide levels in mucosal cells. Finally, the mucosal response to a protein toxin may be under some genetic control. The complete proceedings of this conference will be published by KTK Publishers (Tokyo). The next Joint Conference on Cholera has been scheduled for early November 1984 in Nara, Japan.

Animals↗
PubMed1984

Induction of optimal mucosal antibody responses: effects of age, immunization route(s), and dosing schedule in rats.

The antitoxin response in intestinal mucosa was studied in rats immunized either intestinally or by combined parenteral and intestinal dosing with cholera toxin or cholera toxoid. Attention was given to the duration of enteric priming and the magnitude and time course of mucosal anti-cholera toxin responses in rats of defined age. Cholera toxin given only intraduodenally was a more efficient priming immunogen in young rats than in older rats and caused priming that lasted at least 32 weeks; repeated enteric doses increased local priming and repeatedly evoked vigorous mucosal anti-cholera toxin responses which occurred rapidly and declined slowly. Results differed when a portion of the immunizing regimen was parenteral. Cholera toxoid given intraperitoneally (i.p.) caused mucosal priming that peaked promptly and then rapidly declined; parenteral boosting after enteric priming was much more effective given i.p. than subcutaneously; moreover, the booster response was brief, virtually disappearing within 11 days, and could not be reproduced by a second i.p. immunization. These results accord with evidence that parenteral immunization both stimulates and suppresses mucosal secretory immunoglobulin A responses, whereas local immunization is not known to be suppressive. Evidence for parenterally induced suppression was the rapid decline in mucosal priming after i.p. immunization, the shortened mucosal antibody response after i.p. immunization, and possibly the inability to parenterally evoke a booster response twice. In these studies, the level of priming observed at different intervals after parenteral, enteric, or combined immunization appeared to reflect the sum of priming and suppressive effects evoked by the preceding immunization(s).

Aging↗
PubMed1984

Compared colonizing and immunizing efficiency of toxinogenic (A+ B+) Vibrio cholerae and an A- B+ mutant (Texas Star-SR) studied in adult rabbits.

Four strains of Vibrio cholerae O1 were compared for their ability to colonize and immunize adult rabbit intestine. Three were virulent, toxinogenic (A+ B+) isolates, and one, an A- B+ mutant (Texas Star-SR), was derived by mutagenesis with nitrosoguanidine. When given orally to nonimmune rabbits, virulent strains colonized the small bowel with similar efficiency, whereas Texas Star-SR colonized poorly. Rabbits fed less than 50 CFU of an A+ B+ strain developed marked serotype-specific resistance to recolonization. In contrast, Texas Star-SR evoked resistance to reinfection less efficiently, with a minimum immunizing dose of 10(5) CFU when given once or 10(3) CFU when given twice. Oral inoculation with an A+ B+ strain also evoked vigorous, dose-dependent mucosal antitoxin responses; comparable inocula of Texas Star-SR were much less effective, causing antitoxin responses that were 90 to 95% smaller. Finally, rabbits inoculated once with 10(4) CFU of an A+ B+ strain were markedly protected against experimental cholera or fecal shedding of V. cholerae when challenged with 10,000 times the 50% effective dose of a virulent strain by the RITARD technique. In contrast, an inoculum of 10(4) CFU of Texas Star-SR was nonprotective, and 10(10) CFU was only partially protective. These studies reveal the remarkable efficiency with which virulent V. cholerae evokes intestinal immunity to recolonization or experimental cholera and show that the A- B+ mutant, Texas Star-SR, is substantially less effective.

Animals↗
PubMed1984

Enhanced mucosal priming by cholera toxin and procholeragenoid with a lipoidal amine adjuvant (avridine) delivered in liposomes.

The mucosal adjuvant activity of avridine, a synthetic lipoidal amine [N,N-dioctadecyl-N',N'-(2-hydroxymethyl) propanediamine, previously designated CP-20,961), was studied in rats immunized intraintestinally with cholera toxin or procholeragenoid. Avridine was most efficient as an adjuvant when incorporated into liposomes; liposomes that lacked avridine had no adjuvant effect. Coadministration of avridine-containing liposomes with enteric priming doses of cholera toxin or procholeragenoid enhanced the efficiency of priming for secondary mucosal anti-cholera toxin responses, i.e., the establishment of memory, five- to sevenfold. Avridine-containing liposomes had no significant effect, however, on either the primary mucosal anti-cholera toxin response, when given with the primary dose of antigen, or on the secondary response, when given with the booster dose to previously primed animals. Little or no adjuvant effect occurred when avridine-containing liposomes were given concurrently with antigen, but at a separate mucosal site or parenterally, or at the site of enteric immunization, but 1 day earlier or later. These results support the notion that adjuvants may be developed which enhance the mucosal immunogenicity of locally applied antigens and suggest that liposomes may be effective vehicles for delivery of such adjuvants.

Adjuvants, Immunologic↗
PubMed1983

Procholeragenoid: a safe and effective antigen for oral immunization against experimental cholera.

The immunogenicity and safety of procholeragenoid, a minimally toxic, heat-induced aggregate of cholera toxin (CT), were studied in enterically immunized rats and dogs. Although 99% less toxic than CT, procholeragenoid was only slightly less efficient in causing jejunal anti-CT responses in rats; in contrast, choleragenoid, the nontoxic B subunit pentamer of CT, was much less effective. The immunogenicity of procholeragenoid was due almost entirely to its large-molecular-weight components (MW = 10(6) to 10(7)) and was markedly reduced by preincubation with GM1 ganglioside or treatment with Formalin to eliminate residual toxicity. These findings suggest that molecular aggregation, binding to GM1 receptors on cell membranes, and stimulation of cellular adenylate cyclase each contributed to the effectiveness of procholeragenoid as a mucosal immunogen. In dogs, oral immunization with five 500-micrograms doses of procholeragenoid evoked vigorous anti-CT responses in jejunal mucosa without causing significant diarrhea. When subsequently challenged with virulent Vibrio cholerae, immunized dogs showed 83% protection against the development of severe or lethal diarrhea compared with non-immunized controls. These results confirm a protective role for mucosal antitoxin in experimental cholera and show that procholeragenoid is both safe and effective as an oral immunogen. Procholeragenoid, combined with other antigens of V. cholerae, may constitute a simple, safe, and effective oral vaccine for cholera.

Administration, Oral↗
PubMed1983

Successful colonization and immunization of adult rabbits by oral inoculation with Vibrio cholerae O1.

Adult rabbits were inoculated orally (or duodenally) with virulent Vibrio cholerae O1. Jejunal colonization occurred only when hypoperistalsis was induced at the time of inoculation by tincture of opium given intraperitoneally (or by temporary ileal obstruction). For oral inoculation, prior neutralization of gastric acid was also required. Inoculation with 10(9) V. cholerae caused jejunal colonization for 1 to 2 days and ileal colonization for 5 to 6 days. The extent of small bowel colonization 18 h after oral inoculation was related to inoculum size but also reflected limited multiplication of small inoculum sizes and net death, clearance of large inoculum sizes, or both. Serious diarrhea occurred only in rabbits fed large inoculum sizes, i.e., 10(10) V. cholerae, and then rarely. Rabbits colonized once with 10(10) V. cholerae became highly resistant to recolonization with either the same or opposite serotype. After 18 weeks, these rabbits were still partially protected, whereas twice-colonized rabbits were highly protected. Protection against recolonization appeared to be due, at least partly, to interference with the adherence of V. cholerae to the bowel mucosa, thus allowing rapid removal of V. cholerae when peristalsis resumed. Prior colonization also protected against cholera-like diarrhea in rabbits challenged by the removable intestinal tie-adult rabbit diarrhea technique, the 50% effective dose for severe or lethal diarrhea being increased more than 100-fold, and probably more than 10,000-fold, for challenge with either the homologous or heterologous serotype of V. cholerae. The described rabbit model appears well suited for the study of immunity evoked by enteric colonization with V. cholerae O1.

Administration, Oral↗
PubMed1983

Parenteral immunization causes antigen-specific cell-mediated suppression of an intestinal IgA response.

Rats immunized s.c. with cholera toxin (CT) or toxoid (CTd) show antigen-specific suppression of the jejunal IgA anti-CT response to subsequent enteric doses of CT. We determined whether this effect was partly cell-mediated and studied the suppressor cell response involved. Spleen cells from s.c.-immunized rats suppressed the jejunal anti-CT response in adoptive recipients when cell transfer was at, or 4 days before, intraduodenal priming with CT. Transferred suppression was antigen-specific, and the suppressor cells were nylon wool-nonadherent. Increasing the s.c. dose of CT from 0.1 to 40 micrograms, and the interval between immunization and cell harvest from 2 to 16 wk, each increased the suppressive effect of a constant spleen cell inoculum. After s.c. immunization, suppressor cells were present in the spleen within 1 to 2 wk, among TDL within 4 to 8 wk, and in Peyer's patches and thymus within 8 to 16 wk; this sequence suggested they arose in the spleen and later migrated to mucosae and the thymus. Prior splenectomy did not alter the suppressive effect of s.c. CT, however, nor did it prevent suppressor cell appearance among TDL, indicating that suppressor cells also arose from nonsplenic sites. Transferred suppressor cells acted by interfering with the development of specific immunologic memory within Peyer's patches during enteric priming; transfer of suppressor cells at the time of enteric boosting had no effect upon the secondary mucosal anti-CT response. We conclude that the suppressive effect of s.c. immunization on a specific mucosal IgA response is due largely to the action of systemically derived suppressor cells upon the primary mucosal immune response within Peyer's patches. This sequence resembles the mirror image of oral tolerance, which involves the suppression of systemic IgG and IgM responses by suppressor cells that arise in Peyer's patches and migrate to the spleen after antigen feeding.

Animals↗
PubMed1983

Conjunctival immunity: compared effects of ocular or intestinal immunization in rats.

The ability to induce a conjunctival antitoxin response by conjunctival or enteric administration of cholera toxin antigen was studied in rats. Repeated enteric immunization caused a vigorous jejunal antitoxin response, but none in the conjunctiva. Enteric immunization did, however, prime for a conjunctival antitoxin response to locally applied antigen, as did direct ocular administration of cholera toxin. Vigorous conjunctival antitoxin responses occurred only after ocular challenge, and were localized to the challenged eye. These results agree with the notions that (1) specific memory cells migrate to the conjunctiva after enteric immunization, or arise locally after ocular immunization; and (2) specific antibody-producing plasma cells arise almost entirely within the immunized conjunctiva, and few if any migrate to the conjunctiva from distant mucosae or from the conjunctiva of the immunized eye to that of the nonimmunized eye.

Animals↗
PubMed1982

Oral immunization of dogs with purified cholera toxin, crude cholera toxin, or B subunit: evidence for synergistic protection by antitoxic and antibacterial mechanisms.

The immunogenicity and safety of purified cholera toxin (CT), its B subunit, and a crude culture filtrate of toxigenic Vibrio cholerae (CrT) were compared in dogs immunized orally and challenged with virulent V. cholerae. CT and CrT caused marked protection in two- or three-dose regimens. Protection due to CT occurred only with doses that caused transient, sometimes severe, diarrhea in most dogs; this protection was proportional to the peak antitoxin response in jejunal mucosa and lasted at least 15 weeks. In contrast, minimum protective doses of CrT contained much less cholera toxin, caused very mild diarrhea in only 21% of the dogs, and evoked protection that was greater than predicted from the modest jejunal antitoxin response. B subunit caused smaller jejunal antitoxin responses than did similar doses of CT and was poorly protective, the 50% protective dose being >40-fold greater than that of CT. Two observations indicated that protection due to CrT involved synergy between antibacterial and antitoxic immune responses. First, the 50% protective dose of CrT was 24-fold and >36-fold smaller than the 50% protective doses of its CT and non-CT antigenic components, respectively, when tested separately. Second, protection was greater in CrT-immunized dogs than in CT-immunized dogs for a given mucosal antitoxin response. Low doses of CrT evoked serotype-specific protection, indicating that the serotype-specific O somatic antigen contributed significatly to antibacterial protection. These results suggest that a simple, effective, nonliving oral vaccine for cholera based on combined antibacterial and antitoxic immunity can probably be achieved. However, further studies are needed to determine how a protective antitoxic response can be evoked without causing diarrhea during immunization.

Administration, Oral↗
PubMed1982

Determinants of the localization, magnitude, and duration of a specific mucosal IgA plasma cell response in enterically immunized rats.

The origin and fate of specific IgA plasma cells in intestinal lamina propria were studied in rats immunized enterically with cholera toxin (CT). Our major goal was to define how an anti-CT response is focused and sustained at the site of antigen challenge. To distinguish antigen-dependent from antigen-independent mechanisms, CT exposure was restricted to defined portions of intestine and, in some studies, the distribution of antitoxin-containing plasma cells (ACC) was examined in nonimmune adoptive recipients of post-challenge thoracic duct lymphocytes. After enteric priming and challenge, ACC appeared throughout the gut, but were most numerous at the challenged site. About 25% of ACC appearing at the site of jejunal challenge were due to antigen-driven proliferation of memory cells within the lamina propria; the remainder arose elsewhere, apparently in mucosal follicles or mesenteric lymph nodes, and migrated systemically as antitoxin-containing plasmablasts before homing to the lamina propria. The homing of these migrating ACC precursors was not affected by mucosal exposure to CT, nor did they undergo appreciable antigen-driven division after arrival in gut lamina propria. However, homing was specific for the organ from which they arose, i.e., precursors arising from duodenal challenge homed selectively to jejunum, whereas those from colonic challenge homed to the colon. The organ specificity of homing was determined during the challenge response and was independent of the origin of memory cells participating in the response. The survival of migrating ACC precursors did not differ in segments of gut exposed or nonexposed to CT. However, CT exposure at the time of their migration evoked another secondary-type response, due to stimulation of comigrating memory cells, thus sustaining the secondary response at a high level. These results and those in a previous report identify important mechanisms that affect the localization, magnitude, and duration of a specific IgA response, at least in the intestine. These include: 1) organ-specific homing of migrating IgA plasmablasts, 2) antigen-driven generation of IgA plasma cells from memory cells within the lamina propria, 3) enhanced memory at the site of mucosal priming compared to that a distant mucosae, and 4) regeneration of memory cells during the secondary response.

Animals↗
PubMed1981

Cellular dissemination of priming for a mucosal immune response to cholera toxin in rats.

Using CT as the test antigen, we sought 1) to learn whether primary immunization at 1 mucosal site caused priming of distant nonstimulated mucosae, 2) to study the role of migrating memory cells in the dissemination of mucosal priming, and 3) to compare disseminated priming with priming that occurs at the site of initial immunization. CT given i.c. or i.d. caused priming in tracheal and nonexposed enteric mucosae; i.t. immunization, however, did not cause detectable enteric priming. Adoptive transfer of immune TDLs showed that priming was conveyed by migrating memory cells. These appeared to be of 2 types: those that recirculated briefly before settling in MALT, and those that continued to recirculate until recruited by antigen to the site of mucosal challenge. Both types were required for secondary responses at mucosae distant from the site of priming. The time-course of disseminated mucosal priming resembled that of priming at the site of initial CT exposure, both lasting at least 16 wk. Disseminated priming persisted better in jejunal than tracheal mucosa, suggesting that the subgroup of memory cells that did not continue to recirculate settled preferentially in jejunal MALT. Disseminated priming supported smaller challenge responses than priming at the site of initial CT exposure did, suggesting that sessile memory cells also contributed to the latter process. These observations extend the concept of a "common mucosal immune system" to include cellular dissemination of mucosal priming, but also show quantitative differences between local and disseminated priming that probably reflect the patterns of distribution of migrating and sessile memory cells.

Animals↗