Enhancement of vitamin A combined vitamin D supplementation on immune response to Bacille Calmette-Guérin vaccine revaccinated in Chinese infants.

OBJECTIVE: To investigate whether there is an association between diameter of bacille Calmette-Guérin (BCG) scars and effect of purified protein derivative (PPD) reaction and to determine whether vitamin A (VA) combined vitamin D (VD) supplementation influences the immune response to BCG revaccinated in Chinese infants. METHODS: A cross-section and 3-month community-randomised trial was conducted. A total of 5 629 infants at 3, 6 and 12 months of age in Junan County of China were examined for BCG scar formation. Then, 597 revaccinated infants were randomly assigned to supplementation (n=307) and control (n=290) groups. The supplementation group were daily assigned to 1 500 IU VA and 500 IU VD for 3 months. Then all infants were subjected to skin test with PPD. RESULTS: The diameter of BCG scars was positively correlated with diameter of skin indurations of PPD (r=0.17, P<0.05) in the 5 629 infants. The rate of positive response to PPD was higher in the supplementation group than in the control group (96.1% versus 89.7%, P<0.05, prevalence ratio 1.07, 95% CI 1.02-1.12). The prevalence ratio of PPD response for the supplementation group compared with that for the control group was 1.07 (95% CI 1.01-1.13) for the males and 1.08 (95% CI 1.00-1.17) for the females. For the supplementation group, the males got larger tuberculin induration than the females [(0.73±0.21) cm versus (0.67±0.20) cm, P<0.05) after intervention. CONCLUSIONS: The diameter of BCG scars was effectively correlated with PPD response, which indicates BCG scar formation may be an useful tool to evaluate the effect of tuberculosis prevention. VA combined VD supplementation may play an immuno-regulatory role in BCG revaccination. This may contribute to the prevention of childhood tuberculosis.

Preclinical study and phase I clinical safety evaluation of recombinant Mycobacterium tuberculosis ESAT6 protein.

BACKGROUND: To investigate the ability of rESAT6 to identify different mycobacteria-sensitized guinea pigs and its safety in preclinical and phase I clinical study. MATERIAL AND METHODS: Guinea pigs were sensitized with different Mycobacteria. After sensitization, all animals were intradermally injected with rESAT6 and either PPD or PPD-B. At 24 h after the injection, the erythema of the injection sites were measured using a double-blind method. For the preclinical safety study, different doses of rESAT6 and BSA were given 3 times intramuscularly to guinea pigs. On day 14 after the final immunization, the guinea pigs were intravenously injected with the same reagents in the hind legs and the allergic reactions were observed. A single-center, randomized, open phase I clinical trial was employed. The skin test was conducted in 32 healthy volunteers aged 19-65 years with 0.1 µg, 0.5 µg, and 1 µg rESAT6. Physical examination and laboratory tests were performed before and after the skin test and adverse reactions were monitored. The volunteers' local and systemic adverse reactions and adverse events were recorded for 7 days. RESULTS: Positive PPD or PPD-B skin tests were observed in all Mycobacteria-sensitized guinea pigs; the diameters of erythema were all >10 mm. The rESAT6 protein induced a positive skin test result in the guinea pigs sensitized with MTB, M. bovis, M. africanum and M. kansasii; the diameters of erythema were 14.7±2.0, 9.3±3.8, 18.7±2.4, and 14.8±4.2 mm, respectively. A negative skin test result was detected in BCG-vaccinated and other NTM-sensitized guinea pigs. The rESAT6 caused no allergic symptoms, but many allergic reactions, such as cough, dyspnea, and even death, were observed in the guinea pigs who were administered BSA. During the phase I clinical trial, no adverse reactions were found in the 0.1 µg rESAT6 group, but in the 0.5 µg rESAT6 group 2 volunteers reported pain and 1 reported itching, and in the 1 µg rESAT6 group there was 1 case of pain, 1 case of itching, and 1 case of blister. No other local or systemic adverse reactions or events were reported. CONCLUSIONS: The rESAT6 can differentiate effectively among MTB infection, BCG vaccination, and NTM infection and is safe in healthy volunteers.

Mesoporous silica-calcium phosphate-tuberculin purified protein derivative composites as an effective adjuvant for cancer immunotherapy.

The synthesis of mesoporous silica/calcium phosphate composite loaded with the immunopotentiator tuberculin purified protein derivative (PPD-MS/CaP) as an effective adjuvant for cancer immunotherapy is reported here. The PPD-MS/CaP adjuvant is prepared by immersing mesoporous silica in a supersaturated calcium phosphate solution supplemented with the immunopotentiator PPD for 24 h. PPD is coprecipitated with calcium phosphate inside and on the surface of mesoporous silica. By loading the immunopotentiator PPD in the PPD-MS/CaP adjuvant, an enhanced activation of antigen-presenting cells, such as GM-CSF secretion by THP-1 differentiated macrophages, is obtained probably due to sustained PPD release and an efficient cellular uptake of PPD. The PPD-MS/CaP adjuvant mixed with liquid-N2 -treated tumor tissue effectively triggers anti-tumor immune response and markedly inhibits in vivo tumor growth. The PPD-MS/CaP adjuvant is a promising alternative for cancer immune therapy.

Immune approaches in tuberculosis therapy: a brief overview.

TB is typically caused by Mycobacterium tuberculosis, a symbiotic bacterium present in one-third of the world's population. There any many factors triggering overt clinical disease in a small proportion of humans. In our view the major role in the process is played by the host's immune response, especially self-directed, destructive inflammation. Conventional chemotherapy produces bactericidal or bacteriostatic effects, but immunopathological changes can only be corrected by immunotherapy. Various attempts have been made to identify the optimal immune intervention. Some have shown promising effects, but many have failed. It is commonly believed that the field started in 1890: the year Robert Koch announced his tuberculin therapy. In the Pên Ts'ao Kang Mu, classical Chinese materia medica, published during Ming dynasty, Li Shi Chen (1518-1593) recommended, as a remedy for hemoptysis, to collect from the sputum "…blood lumps, roast them till they are black, and take then them as a powder". In retrospect, this is perhaps the earliest recorded reference relating to immunotherapy of TB with heat-killed mycobacteria. Modern science is obviously geared toward more palatable approach, but without hindsight from often disdained empirical evidence no progress can be made. The clinical experience from various trial and error processes is briefly discussed in this review.

[LOW-INTENSITY LASER THERAPY IN THE PROPHYLACTIC TREATMENT OF TUBERCULIN HYPERERGIC CHILDREN].

The results of sanatorium treatment were analyzed in 156 children and adolescents aged 11-17 years at high risk for tuberculosis. All the patients had been long infected with Mycobacterium tuberculosis with hyperergic tuberculin sensitivity; they had comorbidity and were susceptible to frequent respiratory diseases. A course of percutaneous low-intensity laser irradiation was incorporated as a new method into a complex of prophylactic treatment. The time course of changes in tuberculin sensitivity, serological values, and clinical data were estimated. The proposed treatment regimen was shown to have some advantage over the conventional treatment one.

Effect of high-dose vitamin A supplementation on the immune response to Bacille Calmette-Guerin vaccine.

BACKGROUND: Vitamin A supplementation (VAS) at birth has been associated with decreased mortality in Asia. Bacille Calmette-Guérin (BCG) vaccine is given at birth in tuberculosis-endemic countries. Previous studies suggest that VAS may influence the immune response to vaccines. OBJECTIVE: Our objective was to examine whether VAS influences the immune response to simultaneously administered BCG vaccine. DESIGN: Within a randomized trial of 50,000 IU vitamin A or placebo given with BCG vaccine at birth in Guinea-Bissau, 2710 infants were examined for BCG scar formation and delayed-type hypersensitivity (DTH) to purified protein derivative of Mycobacterium tuberculosis (PPD) at 2 and 6 mo of age. The ex vivo cytokine response to PPD was measured in 607 infants. RESULTS: At 2 mo of age, 39% (43% of the boys and 34% of the girls) responded to PPD. The prevalence ratio of a measurable PPD reaction for VAS compared with placebo recipients was 0.90 (95% CI: 0.80, 1.02) for all infants, 0.81 (95% CI: 0.69, 0.95) for boys, and 1.04 (95% CI: 0.86, 1.26) for girls. At 6 mo of age, 42% of the infants responded to PPD. No difference was observed between VAS and placebo recipients. The prevalence of BCG scar was not affected by VAS. The ex vivo interferon-gamma response to PPD was increased by VAS (means ratio: 1.40; 95% CI: 1.03, 1.91). CONCLUSIONS: VAS with BCG vaccination does not appear to interfere with the long-term immune response to BCG. However, VAS temporarily altered the DTH reaction to PPD in boys at 2 mo of age, suggesting sex differences in the immunologic response to VAS given with BCG. This trial was registered at www.clinicaltrials.gov as #NCT00168597.

Effect of maternal cells transferred with colostrum on cellular responses to pathogen antigens in neonatal calves.

OBJECTIVE: To assess the effect of maternal cells or cellular components on neonatal immune responses to intracellular pathogens in calves. ANIMALS: 15 Holstein calves. PROCEDURES: Calves were fed whole colostrum, frozen colostrum, or cell-free colostrum within 4 hours after birth. Leukocytes were obtained from calves before feeding colostrum and 1, 2, 7, 14, 21, and 28 days after ingestion. Proliferative responses against bovine viral diarrhea virus (BVDV) and mycobacterial purified protein derivatives were evaluated. Dams received a vaccine containing inactivated BVDV, but were not vaccinated against mycobacterial antigens. RESULTS: All calves had essentially no IgG in circulation at birth, but comparable and substantial concentrations by day 1. Calves that received whole colostrum had enhanced responses to BVDV antigen 1 and 2 days after ingestion of colostrum. In contrast, calves that received frozen colostrum or cell-free colostrum did not respond to BVDV. No differences were identified among the 3 groups in response to mycobacterial antigens. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that transfer of live maternal cells from colostrum to neonatal calves enhanced responses to antigens against which the dams had previously responded (BVDV), but not to antigens to which the dams were naïve (mycobacterial purified protein derivatives). Results suggested that cell-mediated immune transfer to neonates can be enhanced by maternal vaccination.

Vitamin A supplementation increases ratios of proinflammatory to anti-inflammatory cytokine responses in pregnancy and lactation.

Vitamin A supplementation reduces child mortality in populations at risk of vitamin A deficiency and may also reduce maternal mortality. One possible explanation for this is that vitamin A deficiency is associated with altered immune function and cytokine dysregulation. Vitamin A deficiency in pregnancy may thus compound the pregnancy-associated bias of cellular immune responses towards Th-2-like responses and exacerbate susceptibility to intracellular pathogens. We assessed mitogen and antigen-induced cytokine responses during pregnancy and lactation in Ghanaian primigravidae receiving either vitamin A supplementation or placebo. This was a double-blind, randomized, placebo-controlled trial of weekly vitamin A supplementation in pregnant and lactating women. Pregnancy compared to postpartum was associated with a suppression of cytokine responses, in particular of the proinflammatory cytokines interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha. Mitogen-induced TNF-alpha responses were associated with a decreased risk of peripheral parasitaemia during pregnancy. Furthermore, vitamin A supplementation was significantly associated with an increased ratio of mitogen-induced proinflammatory cytokine (IFN-gamma) to anti-inflammatory cytokine (IL-10) during pregnancy and in the postpartum period. The results of this study indicate that suppression of proinflammatory type 1 immune responses and hence immunity to intracellular infections, resulting from the combined effects of pregnancy and vitamin A deficiency, might be ameliorated by vitamin A supplementation.

Preoperative CEA and PPD values as prognostic factors for immunochemotherapy using PSK and 5-FU.

PURPOSE: Immunochemotherapy using PSK used as postoperative adjuvant chemotherapy for colorectal cancer in Japan, is a treatment that depends on the immunocompetence of the host. Therefore, we analyzed the data of Hokuriku district conducted by the CIP study group to compare the long-term survival for preoperative CEA level and PPD reaction. PATIENTS AND METHODS: Between February 1991 and March 1993, 87 patients with primary colon cancer and macroscopic lymph node metastasis (macroscopic Dukes' C) underwent macroscopic curative resection. The patients were randomly allocated to receive 5-FU/PSK therapy or 5-FU alone. The 7-year disease-free survival (DFS), 7-year overall survival (OS) and 7-year cancer death survival (CDS) were compared using the preoperative CEA levels and PPD values. RESULTS: In cases with preoperative CEA level > or =3.0 ng/mL, the 7-year DFS, 7-year OS and 7-year CDS were significantly better in the PSK group (85.7, 90.5, 90.5%) than in the control group (52.4, 52.4, 57 1%; p=0.019, 0.007, 0.014,). In cases with preoperative PPD level <19.0 mm, the 7-year DFS, 7-year OS and 7-year CDS were significantly better in the PSK group (85.7, 85.7, 89.3%) than in the control group (56.7, 60.0, 63.3%; p=0.018, 0.036, 0.028). Recurrence was significantly less in the PSK group. The DFS tended to be superior in the PSK group (87.4%) compared to the control group (69.9%) for hematogenous metastasis. CONCLUSION: The present study demonstrated that preoperative CEA and PPD, that can be measured easily in the clinical setting, may be effective indicators of postoperative adjuvant immunochemotherapy using PSK.

Modulation of delayed-type hypersensitivity responses in hairless guinea pigs by peptides derived from enkephalin.

Although opioid peptides such as methionine (met)-enkephalin have been previously shown to enhance or suppress immune responses, few studies in animal models have addressed the immunomodulatory activity of their metabolic derivatives. Hairless (IAF/HA-HO) guinea pigs immunized with Freund's complete adjuvant containing Mycobacterium tuberculosis and repeatedly skin tested with purified protein derivative of tuberculin (PPD) display high levels of stable delayed-type hypersensitivity (DTH) to PPD. Met-enkephalin (YGGFM) and two of its metabolites (YGG, YG) enhanced and accelerated PPD-elicited DTH inflammatory reactions when injected together with elicitor in these animals. At 24 h, 5 x 10(-3) pmol met-enkephalin significantly enhanced DTH responses by 30% over PPD alone, while 5 x 10(-5) pmol of YGG and 5 x 10(-9) pmol of YG significantly enhanced these responses by 62 and 32%, respectively. At much higher doses (5 x 10(3) pmol), met-enkephalin and its metabolites significantly suppressed DTH reactions by 25-32%. Tyrosine and glycine had no effect on PPD-elicited DTH. All DTH reactions (control, enhanced, suppressed) displayed typical perivascular mononuclear cell infiltrates. We conclude that the immunoactivity of met-enkephalin resides in its first two amino acids and suggest that cleavage of enkephalin molecules to YG occurs in serum and/or on the cell surface.

In utero priming of allergen-specific helper T cells.

BACKGROUND: Allergic diseases are major health problems in developed countries. Cord blood mononuclear cells (CBMC) at birth can proliferate after stimulation with allergen and this has led to the widespread view that the sensitization of the fetal immune system by allergens is a key determinant in establishing immunological bias towards allergy. However, the notion that the immune system can be primed by allergen in utero remains unproven. Determination of the CD45 isoform of responding T helper cells is an established method of determining the activation status of responding T helper cells because unsensitized cells express CD45RAhigh and previously sensitized cells CD45ROhigh. OBJECTIVE: To determine if sensitization of allergen-specific T helper cells can occur in utero by determining the CD45 isoform of CBMC proliferating in response to allergen. METHODS: CBMC proliferative responses were measured after stimulation in culture with a panel of allergens, mitogen and control antigen. To ascertain whether any responding T helper cells had been primed in utero, depletion experiments established whether they carried the CD45ROhigh marker of previous activation or the CD45RAhigh marker of unstimulated T cells. RESULTS: CBMC from a high proportion of 223 randomly selected neonates were stimulated to proliferate in vitro by allergens, with 76% responding to timothy grass pollen. In 50% of such responses to timothy grass, the CD45 isoform of the T cells that proliferate indicated that they had been previously activated. However, the remaining 50% of responses to timothy grass were mediated by previously unstimulated T cells. Proliferative responses mediated by CBMC sensitized in utero tended to be greater in magnitude than those mediated by unsensitized cells (P = 0.08). Seventy-five per cent of CBMC samples proliferated after stimulation with mycobacterial PPD and, as in BCG-vaccinated adults, all such CBMC proliferative responses at birth were predominately mediated by sensitized cells. CONCLUSION: Allergen- and antigen-specific Th cells can be primed in utero.

Mercury-reactive lymphocytes in peripheral blood are not a marker for dental amalgam associated disease.

OBJECTIVES: The popular press and publications associated with alternative medicine increasingly report that chronic ill health, particularly myalgic encephalitis like conditions, are associated with mercury amalgam fillings. There are no scientifically proven definitive tests to support these claims. One of the more scientific tests in vogue is to assess the level of blood-borne mercury-reactive lymphocytes and to conclude that patients with high levels have developed a hypersensitivity reaction to mercury. The objective of this study was to determine the diagnostic value of this test. METHODS: This study represents an open comparison of mercury-reactive lymphocyte levels in healthy control individuals with those in patients complaining of symptoms associated with adverse effects of dental metal amalgam fillings. The healthy control group consisted of 51 male and female individuals, aged between 12 and 82 years, with and without dental amalgam fillings. The patient group consisted of 70 male and female individuals, aged between 12 and 87 years, and with the exception of one patient, with three or more mercury amalgam fillings of more than 1 year's duration. In vitro lymphocyte responses to mercury, and to nickel, as an example of a metal commonly associated with hypersensitivity reactions, and to more conventional protein antigens were determined. RESULTS: In the blood of patients and controls, there were similar levels of specifically reactive lymphocytes to all of the in vitro stimulating agents, but there were significantly higher numbers of sub-normal and non-responders within the patient group. CONCLUSIONS: The incidence and quantity of mercury-reactive lymphocytes in the blood are not pathogenic markers of illness associated with dental metal amalgams, but may rather reflect exposure to mercury. The clinical relevance of the decreased in vitro lymphocyte responses in the patient group needs further investigation.

Comparison of immunopharmacological actions of 8 kinds of kampo-hozais clinically used in atopic dermatitis on delayed-type hypersensitivity in mice.

We studied here the effects of 8 kinds of kampo-hozais clinically used to treat atopic dermatitis (Shofu-san, Toki-inshi, Unsei-in, Oren-gedoku-to, Ji-zuso-ippo, Jumi-haidoku-to, Juzen-taiho-to, Hochu-ekki-to) on delayed-type hypersensitivity (DTH), using three types of murine models such as picryl chloride (PC)-induced (contact hypersensitivity), sheep red blood cell (SRBC)-induced (Jones-Mote's reaction) and tuberculin-induced DTH response, in order to clarify and to compare the immunopharmacological action of kampo-hozais. Most of the kampo-hozais investigated here suppressed PC-induced contact hypersensitivity, especially at the inductive phase. Comparing the efficacies of these kampo-hozais on the three types of DTH responses in mice, they were generally divided into 4 groups. Shofu-san significantly reduced PC-induced and tuberculin-induced DTH responses but not a SRBC-induced DTH response. On the other hand, Toki-inshi reduced contact hypersensitivity, tuberculin type DTH response and Jones-Mote's reaction. Ji-zuso-ippo and Juzen-taiho-to suppressed mainly Jones-Mote's reaction, and Unsei-in, Oren-gedoku-to and Jumi-haidoku-to intensively suppressed contact hypersensitivity. We thought that these findings could help us understand how to use these kampo-hozais properly.

Conjugation to preadsorbed preactivated proteins and efficient generation of anti peptide antibodies.

A solid phase conjugation method is described based on the preadsorption of proteins to aluminium hydroxide adjuvant followed by activation of the adsorbed carrier proteins with iodoacetic acid N-hydroxysuccinimidester or other conjugation reagents. Cysteine-containing peptides were coupled to the iodoacetic acid-activated carrier-adjuvant particles through their SH groups. No dialysis is required since the reaction product is isolated at each step of the procedure by a simple centrifugation and can easily be extensively washed between individual manipulations. The method generates peptide-carrier-adjuvant particles with sterically defined presentation of the peptides at the surface of the particles. When used for immunization of mice and rabbits the conjugates elicited high-titered specific anti-peptide sera, which reacted well with the parent protein in ELISA. The strongest reactions were with the denatured form of the parent protein. On immunoblots antisera to the N- and C-terminus of calreticulin recognized the same M, 52,000 protein.

IL-13 production by allergen-stimulated T cells is increased in allergic disease and associated with IL-5 but not IFN-gamma expression.

Interleukin-13 (IL-13) shares many, but not all, of the properties of the prototypic T-helper type 2 (Th2) cytokine IL-4, but its role in allergen-driven T-cell responses remains poorly defined. We hypothesized that allergen stimulation of peripheral blood T cells from patients with atopic disease compared with non-atopic controls results in elevated IL-13 synthesis in the context of a 'Th2-type' pattern. Freshly isolated peripheral blood mononuclear cells (PBMC) obtained from sensitized atopic patients with allergic disease, and non-atopic control subjects, were cultured with the allergens Phleum pratense (Timothy grass pollen) or Dermatophagoides pteronyssinus (house dust mite) and the non-allergenic recall antigen Mycobacterium tuberculosis purified protein derivative (PPD). Supernatant concentrations of IL-13, along with IL-5 and interferon-gamma (IFN-gamma) (Th2- and Th1-type cytokines, respectively) were determined by enzyme-linked immunosorbent assay (ELISA). Allergen-induced IL-13 and IL-5 production by T cells from patients with allergic disease was markedly elevated (P = 0.0075 and P = 0.0004, respectively) compared with non-atopic controls, whereas IFN-gamma production was not significantly different. In contrast to allergen, the prototypic Th1-type antigen M. tuberculosis PPD induced an excess of IFN-gamma over IL-13 and IL-5 production, and absolute concentrations of cytokines were not affected by the presence or absence of atopic disease. Addition of exogenous recombinant IFN-gamma or IL-12, cytokines known to inhibit Th2-type responses, significantly inhibited allergen-driven production of both IL-13 and IL-5, but not T-cell proliferation, whereas exogenous IL-4 did not significantly affect production of IL-13 or IL-5. We conclude that allergen-specific T cells from atopic subjects secrete elevated quantities of IL-13 compared with non-atopic controls, in the context of a Th2-type pattern of cytokine production.

Effect of early vitamin A supplementation on cell-mediated immunity in infants younger than 6 mo.

One hundred twenty infants were randomly assigned to receive either 15 mg vitamin A or placebo with each of three DPT/OPV (diphtheria, pertussis, tetanus/oral polio vaccine) immunizations at monthly intervals. Sixty-two received vitamin A and 58 received placebo. One month after the third supplementation dose, the response to the delayed cutaneous hypersensitivity test [multitest cell-mediated immunity (CMI) skin evaluation] for tetanus, diphtheria, and tuberculin (purified protein derivative, PPD) was the same in the vitamin A and placebo infants. The number of anergic infants was 17 (27%) and 19 (33%) in the vitamin A and placebo groups, respectively. The number of positive tests among well-nourished infants was significantly higher than that in malnourished infants irrespective of supplementation (P < 0.001). Among the infants with adequate serum retinol concentrations (> 0.7 mumol/L) after supplementation, the vitamin A-supplemented infants had a significantly higher proportion of positive CMI tests than the placebo infants (chi-square test: 8.99, P = 0.008). Among the infants with low serum retinol concentrations (< 0.7 mumol/L) after supplementation, vitamin A supplementation had no effect on CMI response. These results indicate that CMI in young infants was positively affected by vitamin A supplementation only in those infants whose vitamin A status was adequate (ie, serum retinol > 0.7 mumol/L) at the time of the CMI test. CMI was consistently better in well-nourished infants irrespective of supplementation.

Differential mycobacterial 65-kDa heat shock protein T cell epitope recognition after adjuvant arthritis-inducing or protective immunization protocols.

Immunization of Lewis rats with heat-killed Mycobacterium tuberculosis (Mt) in mineral oil induces adjuvant arthritis (AA), associated with T cell responses to residues 180-188 of the mycobacterial 65-kDa heat shock protein (hsp65). Preimmunization with hsp65 protects rats against AA and other forms of arthritis. Several explanations for these protective effects have been proposed, including enhanced responsiveness to protective epitopes in hsp65, down-regulation of T cell responses to the 180-188 epitope, and activation of self-hsp60-reactive T cells. To assess the potential of these hypotheses, we analyzed hsp65 T cell epitopes recognized after immunization of Lewis rats with Mt or hsp65. Here we identify nine RT1.B1-restricted T cell epitopes in hsp65. Mt immunization induced T cell responses in which the 180-188 epitope was dominant, whereas hsp65 immunization resulted in a co-dominance of this and two further epitopes, 216-225 and 226-235. Two minor epitopes were recognized after hsp65 but not Mt immunization. These results indicate that hsp65 preimmunization does not down-regulate responses to the AA-associated epitope, but does enhance responses to several hsp65 epitopes that are minor or absent after the AA-inducing immunization protocol. Cross-reactive T cell recognition of hsp65 and rat hsp60 was limited to a single epitope (256-265), recognized after hsp65 immunization, but poorly recognized after Mt immunization. This study provides the necessary basis for elucidating the T cell events involved in the protective effects of hsp65 preimmunization.

A new tripeptide, Pol 509, influences biochemical events associated with antigen presentation efficiency of PPD-specific EBV-B cells.

A synthetic tripeptide (pGLU-LEU-TRP-OCH3) Pol 509, derived from snake venom, was studied directly by analyzing the interactions with synthetic lipid bilayers using NMR spectroscopy. Functional studies were also performed by measuring the effects: i), on early biochemical events (adenyl cyclase and phospholipase C activation products), intermediate (surface Ag expression) and late (DNA synthesis) parameters following B-cell activation elicited by PPD-linkage to specific membrane Ig; and ii), on the presentation of PPD to Ag-specific T-cell lines. Comparative experiments using PMA and IFN-gamma were also performed. We found that all parameters studied were affected by Pol 509 treatment. In fact, while PPD linkage to mlg reversed the balance between cAMP and IP3 existing in unstimulated EBV-B cells, Pol 509 reduced the PPD-induced accumulation of cAMP to control values and induced a further decrease of IP3 level. Pol 509-mediated decrease of these second messenger levels was accompanied by a slight increase of HLA-DR molecule expression and DNA synthesis inhibition. Furthermore, Pol 509 enhanced the efficiency of PPD presentation to T-cell lines. Taken together, these observations suggest that Pol 509, which enhances Ag presentation by modifying second messenger levels, may be considered as a new immunomodulatory drug with immunopotentiating activity.

[In vitro transfer of immunity against PPD with dialyzable extract of leukocytes from human colostrum]. / Transferencia in vitro de inmunidad a PPD con extracto dializable de leucocitos de calostro humano.

The aim of this study is to demonstrate the transference of PPD hypersensibility in an in vitro model, with dialysable colostral leukocyte extract (DCLE) of PPD+ and PPD-mothers, through measurements of leukocyte migration inhibition factor activity (LIF) from blood obtained of the umbilical cord of newborns from PPD+ mothers. The results show that DCLE PPD+ incubated with leukocytes of newborns from PPD- mothers had inhibition of leukocyte migration compared with migration of leukocytes incubated with DCLE PPD-. These results suggest that in this in vitro model, DCLE transfers hypersensibility to PPD.