Individual variation is the key to the development of a vaccine against Staphylococcus aureus: a comparative study between mice lineages

Bacterial infections occur worldwide and are a major public health problem. Among pathogens, Staphylococcus aureus is the main causative agent of bacterial diseases in the world. This study aimed to evaluate which components of the immune system could act protectively against a S. aureus infection in intradermally immunized mice. C57BL/6 and A/j mice were immunized intradermally with S. aureus inactivated by heat and then challenged with viable strains in an air pouch model. At 6, 12, and 24 h after the challenge, euthanasia was performed, and the cellular profile of the inflammatory infiltrate, cytokines, and the bacterial load were evaluated in the air pouch lavages. Immunized mice demonstrated that the intradermal immunization with S. aureus promoted protection in C57BL/6 mice by reducing the bacterial, which was correlated with increased serum concentration of IgG antibodies (IgG1 and IgG2a) against S. aureus. The increase in IgG2a antibody levels was correlated with a decrease of bacterial load in intradermally immunized C57BL/6 mice, along with production of IL-17A at the inflammation site, as well as IgG1consumption. Similar results were not found in the A/j lineage. In conclusion, a vaccine against S. aureus should focus more on the individual characteristics of the host because it is a determinant factor for the success of the immunization.

GAPDH activity and immunogenicity of Staphylococcus aureus recombinant GapC protein / 生物工程学报

In order to characterize the Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activity, immunogenicity and immunoprotection of the Staphylococcus aureus (S. aureus) surface protein GapC, gapC gene of S. aureus was amplified from strain BMSA/855/23-1 by PCR, and was inserted into pQE-30 vector subsequently. The recombinant plasmid, designated as pQE/gapC, was transformed into E. coli strain M15 (pREP4). The recombinant GapC fusion proein was successfully expressed in E. coli M15 induced with IPTG and its GAPDH activity was confirmed by GAPDH activity assay. Then, the recombinant GapC protein, inactivated S. aureus whole cell and placebo (PBS) were administrated to healthy rabbits respectively. The IgG antibody titers, concentration of IFN-gamma and IL-4 cytokines in immunized rabbit sera were measured with Enzyme-Linked Immunosorbnent Assay (ELISA). Finally, immunized rabbits were challenged with S. aureus strain Wood46 to evaluate the immunoprotection. The IgG antibody titers against GapC and whole cell in rabbit sera reached their peaks at day 28 after boost immunization (1:64,000). The concentration of IL-4 and IFN-gamma in GapC groups rabbit sera increased significantly (P<0.05) at day 14 after boost immunization, while the concentration of those in whole cell group did not increase (P>0.05) compared with the placebo group. 4 rabbits in 5 of the protein immunized group were protected against challenge with 1 x 10(8) CFU S. aureus. The results above indicate that the expressed recombinant GapC protein have high GAPDH activity and immunogenicity, can also protect against S. aureus challenge to some extent. S. aureus GapC protein could be an attractive target for further genetic engineering vaccine.

Evaluation of the humoral immune response in BALB/c mice immunized with a naked DNA vaccine anti-methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is the major pathogen involved in nosocomial infections, leading to high rates of morbidity and mortality in hospitals worldwide. The methicillin resistance occurs due to the presence of an additional penicillin-binding protein, PBP2a, which has low affinity for b-lactam antibiotics. In the past few years, vancomycin has been the only antibiotic option for treatment of infections caused by multiresistant MRSA; however, reports of vancomycin-resistant strains have generated great concerns regarding the treatment to overcome these infections. In the present study, we report preliminary results regarding the humoral immune response generated in BALB/c mice by two different doses of naked DNA vaccine containing an internal region, comprising the serine-protease domain, of the PBP2a of MRSA. The immunization procedure consisted of four immunizations given intramuscularly within 15-day intervals. Blood was collect weekly and anti-PBP2a-specific antibodies were screened by ELISA. BALB/c mice immunized with DNA vaccine anti-PBP2a have shown higher antibody titers mainly after the fourth immunization, and intriguingly, no correlation between the humoral immune response and DNA dose was observed. Our results suggest that the DNA vaccine anti-PBP2a induced an immune response by production of specific antibodies anti-MRSA in a non-dose-dependent manner, and it could represent a new and valuable approach to produce specific antibodies for passive immunization to overcome MRSA infections.

Inmunoterapia sublingual en el tratamiento de la linfangitis recidivante / Sublingual Immunotherapy in the treatment of relapsing Lymphangitis

Se plantea actualmente que la inmunoterapia sublingual activa los mecanismos inmunoreguladores, a través del drenaje hacia los ganglios linfáticos regionales, por lo que no parecen existir razones teóricas para dudar del potencial de esta vía de liberación antigénica para la inmunoterapia. Como método se realizaron cuantificación de inmonogloibulinas y de inmunocomplejos circulantes, encontrándose los mismos dentro del rango de los valores normales... En función de los resultados obtenidos, los autores concluyen que la inmunoterapia sublingual con extractos bacterianos puede ser una alternativa válida para el tratamiento de la linfangitis recidivante

Uso de vacuna bacteriana de Staphylococcus en pacientes pediátricos con sinusitis crónica / Use of Staphylococcus bacterial vaccine in pediatric patients with chronic synusitis

Introducción. Los extractos antigénicos de vacuna bacteriana (Staphylococcus aureus) incrementan la fagocitosis, las concentraciones de inmunologlobulinas y ayudan en la respuesta inmunológica. Objetivo. Determinar la eficacia de la vacuna bacteriana en pacientes pediátricos con sinusitis crónica. Material y método. A través de un estudio prospectivo, observacional, descriptivo y longitudinal se estudiaron 50 pacientes con diagnóstico clínico y radiológico de sinusititis crónica en el periodo de mayo de 1997 a julio de 1998; se trataron con tres esquemas de antibióticos, se les efectuaron estudios de citología hemática, de moco, exudado faríngeo y determinación de inmunoglobulinas y radiografías de senos paranasales. Se aplicó el extracto de 0.1 ml hasta 0.5 ml dos veces por semana, vía subcutánea durante ocho meses, con seguimiento de seis meses y control de citología hemática, así como determinación de inmunoglobulinas. Resultados. 82 por ciento (41) de los pacientes mejoraron y nueve (18 por ciento) persistieron con síntomas, de éstos cinco requirieron la prescripción de antimicrobianos, tres amigdalectomía. Hubo un incremento de inmunoglobulina, principalmente de la IgA e IgG en 38 (76 por ciento) pacientes