Erythema multiforme following vaccination in an infant.

Erythema multiforme is a cutaneous reaction pattern precipitated by varied agents, notably herpes simplex and drugs. It predominantly occurs in adolescents and young adults but may be seen at other ages also. While vaccination is rarely a precipitating factor for erythema multiforme, it may occasionally be seen in infants and children. We report here a case of a two month-old infant with lesions of erythema multiforme minor appearing after two weeks following vaccination for DPT, Hepatitis B and influenza.

Una vacuna para la lepra: evaluación de su necesidad y estrategia de desarrollo

Las vacunas vivas atenuadas como la BCG aunque han demostrado capacidad de estimular una respuesta inmunológica protectora en humanos en algunos ensayos clínicos, no resultan actualmente las más apropiadas con la gran cantidad de infectados HIV ya que podrían por sí mismas ser causa de enfermedad. Este trabajo revisa las necesidades actuales y posibilidades de aplicación de una vacuna frente a la lepra diseñada con los planteamientos y conocimientos proporcionados por las nuevas tecnologías, sobre todo en los campos de la Inmunología y Biología Molecular (AU)

Anti-leprosy protective vaccination of rhesus monkeys with BCG or BCG plus heat-killed Mycobacterium leprae: lepromin skin test results.

Groups of rhesus monkeys (RM) were vaccinated and boosted with living Mycobacterium bovis Bacillus Calmette-Guerin (BCG) or BCG + low dose (LD) heat-killed Mycobacterium leprae (HKML) or high dose (HD) HKML or were unvaccinated. Animals vaccinated with BCG + LD and HD HKML were lepromin skin tested 2 weeks after boosting. All groups were lepromin tested 37 and 46 months after challenge with live M. leprae. Fernandez (72 h) and Mitsuda (28 day) responses were recorded. Ten of 10 rhesus monkeys in each of the two BCG + HKML-vaccinated groups significantly converted to strong positive Fernandez status within 2 weeks of boosting, compared to one of six positives in the unvaccinated unchallenged normal control group. Both BCG + HKML groups were significantly protected from clinical leprosy. Six of 10 in each of the two BCG + HKML groups significantly converted to Mitsuda positivity within 2 weeks of boosting compared to zero of six in the normal control group. The sizes of the Mitsuda responses were larger in the LD group than the HD HKML vaccinated/boosted group, suggesting suppression by vaccination with higher doses of HKML in combination with BCG. Fernandez responses were negative in normal RM as well as in the unvaccinated, ML-challenged group and the BCG-vaccinated, ML-challenged group at 37 or 46 months after ML inoculation, although the BCG-vaccinated group was significantly protected from leprosy and the unvaccinated group was not. In contrast, at 37 months the Fernandez reaction was positive in the BCG plus LD and the BCG plus HD HKML-vaccinated groups, both of which were significantly protected from clinical leprosy. By 46 months, the Fernandez responses were below significance in all groups. Thus, Fernandez reactivity is not a reliable correlate to protection from experimental leprosy in RM. Mitsuda responses became strongly positive in all four ML-challenged groups by 37 months and remained strongly positive at 46 months after ML inoculation, suggesting that strong Mitsuda reactivity reflects responses to living ML. BCG or BCG + LD or HD HKML vaccination/boosting of RM produced significant clinical protection from leprosy and there was a good correlation between protection from LL forms of leprosy and positive Mitsuda skin test responses after challenge with live ML. Positive Mitsuda responses were generated in essentially all individuals after challenge with live ML, and this response was primed by prior vaccination/boosting with BCG + HKML as shown by conversion to positivity 2 weeks after boosting. The data show that resistance to clinical leprosy is reflected by Mitsuda responses in ML-exposed RM, similar to results from human studies, and confirm the suitability of RM as a model for leprosy vaccine studies.

Heat shock protein micro-encapsulation as a double tool for the improvement of new generation vaccines

The modern vaccinology encompasses the recombinant DNA technology, protein and carbohydrate chemistry to obtain safe molecularly defined vaccines. Nevertheless most of the vaccines are poorly immunogenic because a large number of antigens are membrane proteins and consequently they are not present in their active conformation in the vaccine. Others are not as potent because they contain only B epitopes and therefore, cannot stimulate cellular memory. We have been studying the characteristics of the recombinant heat shock protein 18kDa-hsp from Mycobacterium leprae as an alternative carrier protein with a T epitope source to enhance the activity of these second generation vaccines. Here we proved that the 18kDa-hsp acted as carrier, without masking the activity of the carried antigen, with similar immune stimulatory effect when compared with ODN1668. Supramolecular aggregates of 18kDa-hsp and Mice serum albumin (MSA) were obtained using glutaraldehyde as cross linker. The Neisseria meningitides serogroup C polysaccharide (PSC, a B epitope) and the carrier protein 18kDa-hsp were co-encapsulated within Soybean phosphatidylcholine liposomes (SPC: Cho : alpha-Toc, 22 : 5 : 0.18 molar ratio, respectively). These liposomes were prepared in MPB buffer (20 mM phosphate, 295 mM mannitol pH 7.2) in the presence or absence of the ODN1668, TCCATGACGTTCCTGATGCT. When mice were injected with 18kDa-hsp-MSA no antibody against the MSA was observed. This means that the 18kDa-hsp acted as carrier, without masking the carried protein immune activity. Stable liposomes of 150 nm were obtained using mannitol as a cryoprotector. Genetically selected mice when injected with liposomes containing PSC and 18kDa-hsp displayed an antibody titer of 12. In contrast, in those mice injected with free PSC there was no response.

Antileprosy protective vaccination of rhesus monkeys with BCG or BCG plus heat-killed Mycobacterium leprae: immunologic observations.

Groups of rhesus monkeys were vaccinated and boosted with Mycobacterium bovis bacillus Calmette Guerin (BCG) or BCG plus low-dose (LD) or high-dose (HD) heat-killed M. leprae (HKML), or were unvaccinated. Prior to and following vaccination-boosting and subsequent M. leprae (ML) challenge, these and unvaccinated, unchallenged control monkeys were observed longitudinally for approximately 3 years. Vaccination with BCG plus HKML initially stimulated significant in vitro blood mononuclear cell blastogenic responses to lepromin, which returned to baseline post-boosting and post-live-ML-challenge, minimally reappearing significantly 2 years post-ML-challenge. Vaccination with BCG failed to stimulated positive blastogenic responses to lepromin before ML-challenge but small, marginally positive, intermittent responses were seen post-ML-challenge. Compared to the unvaccinated ML-challenged group, significant increases in the numbers of blood CD4+ and CD8+ T-cell subsets and an increased CD4+:CD8+ ratio were observed in both BCG plus HKML-vaccinated, ML-challenged groups, but not in the BCG-only-vaccinated, ML-challenged group. CD4+CD29+ and CD4+CD45RA+ subset numbers increased significantly over time in only the BCG plus LD HKML-vaccinated, ML-challenged group. Compared to unvaccinated, ML-challenged groups, vaccination with BCG or BCG plus HKML followed by ML-challenge produced lower IgM:IgG antiphenolic glycolipid-I (PGL-I) serum antibody ratios and protected rhesus monkeys from clinical leprosy, consistent with prior observations that low IgM:IgG anti-PGL-I responses correlated with resistance to and protection from leprosy.

Antileprosy protective vaccination of sooty mangabey monkeys with BCG or BCG plus heat-killed Mycobacterium leprae: immunologic observations.

Groups of sooty mangabey monkeys (SMM) were vaccinated and boosted with Mycobacterium bovis bacillus Calmette-Guerin (BCG), or BCG + low-dose (LD) or high-dose (HD) heat-killed M. leprae (HKML), or were unvaccinated. Prior to and following vaccination-boosting and subsequent M. leprae (ML) challenge, these and unvaccinated, unchallenged control monkeys were immunologically observed longitudinally for approximately 3 years. SMM [multibacillary (MB) leprosy-prone as a species] were not protected clinically by BCG or BCG + HKML, although the disease progress was slowed by vaccination with BCG alone. The longitudinal immune response profiles to BCG or BCG + HKML in SMM showed that: 1) vaccination with BCG or BCG + HKML initially stimulated significant in vitro blood mononuclear cell blastogenic responses to ML antigens, which returned to baseline post-boosting and post-live ML challenge; 2) BCG + LD HKML-vaccinated groups gave the largest blastongenic response (SI = 23) followed by the BCG + HD HKML group (SI = 14.5) and by the BCG-only vaccinated group (SI = 3.6); 3) significantly diminished numbers of blood CD4+ (helper) and CD4+CD29+ (helper-inducer) T-cell subsets were observed longitudinally in all ML-challenged groups compared to controls regardless of whether they had been vaccinated or not; 4) CD8+ (suppressor) T-cell numbers remained longitudinally constant, on average, in all ML-challenged groups (vaccinated or not) compared to controls; 5) there was a significant decrease in the CD4+:CD8+ ratio over time in all ML-challenged groups (vaccinated or not); 6) vaccination with BCG or BCG + LD or HD HKML resulted in significantly increased numbers of CD4+CD45RA+ (suppressor-inducer) T cells longitudinally compared to the unvaccinated, ML-challenged control group; and 7) over time, vaccination with BCG + HKML followed by live ML-challenge produced higher IGM:IgG antiphenolic glycolipid-I (PGL-I) serum antibody response ratios than BCG-only vaccinated, ML-challenged monkeys or unvaccinated, ML-challenged SMM, consistent with prior observations that IgG anti-PGL-I responses correlate with resistance to and protection from clinical leprosy and IgM anti-PGL-I responses correlate with increased susceptibility.

Restoration of proliferative response to M. leprae antigens in lepromatous T cells against candidate antileprosy vaccines.

Several studies conducted in the last decade suggest that Mycobacterium lepraereactive T cells exist in lepromatous patients, but their number may be too few to yield a detectable response in cell-mediated immunity (CMI) assays. Immunizations with candidate antileprosy vaccines and stimulation of T cells with M. leprae + interleukin-2 restore the M. leprae-induced CMI response in lepromatous leprosy patients. These immunizations and stimulation may enrich the pre-existing M. leprae-responsive T cells in lepromatous patients and, thereby, induce a detectable CMI response to M. leprae antigens upon repeat testing. To verify this proposition, we carried out a study in a group of 10 lepromatous leprosy patients. Peripheral blood mononuclear cells (PBMC) obtained from these patients were anergic to M. leprae antigens in proliferative assays, but they responded to the antigens of candidate antileprosy vaccines, i.e., M. bovis BCG, M. bovis BCG + M. leprae, and Mycobacterium w. The enrichment of M. leprae-responsive T cells was performed by establishing T-cell lines from the PBMC after in vitro stimulation with M. leprae, M. bovis BCG, M. bovis BCG + M. leprae, and Mycobacterium w. When tested for their proliferative responses, 1/10, 3/10, 6/10 and 2/10 T-cell lines established against M. leprae, M. bovis BCG, M. bovis BCG + M. leprae, and Mycobacterium w, respectively, responded to M. leprae. These results suggest that enrichment of pre-existing M. leprae-responsive T cells may contribute to the restoration of the T-cell response to M. leprae in some lepromatous patients. Four of the 10 M. leprae-induced T-cell lines proliferated in response to the 65 kDa, 36 kDa, 28 kDa, and 12 kDa recombinant antigens of M. leprae, suggesting that the nonresponsiveness of T cells in some lepromatous patients may be overcome by using recombinant antigens of M. leprae.