The detection of antigenic determinants of Acinetobacter baumannii.

BACKGROUND: Acinetobacter baumannii continues to pose a threat to burdened patients in ICUs all around the world. Lately, infection control techniques are not sufficient to curb A. baumannii's progression and chemotherapeutics are losing their potency against it. Thus, immunization became a key player in providing an ideal solution to the dilemma. None of the vaccines under investigation have reached the market and the search for a tailored vaccine remains a challenge. The notion of unravelling the bacterial antigens to design a novel epitope-based vaccine proved its merits. METHODS: In this work, the propitious polysaccharide and protein antigenic determinants of A. baumannii were mapped by mimicking the infection. The immune response was evaluated by western blot, ELISA, and cellular proliferation assay techniques. RESULTS: The screening showed that OMPs induced the most eminent sustained IgG response. In addition, OMP gave the highest cellular proliferation and a fold increase in ELISA that reached up to 10-fold by week 6. Whilst, the LPS gave a rapid IgM response, that reached 5-fold and the response was visible from week 1 in the western blot. The OMPs had a more pronounced effect in eliciting a cellular immune response. CONCLUSION: The results elaborated the valuable role of using pure OMPs and detoxified LPS together; as a major cornerstone in designing an ideal vaccine against A. baumannii.

Development of immunization trials against Pasteurella multocida.

Pasteurellosis is one of the most important respiratory diseases facing economically valuable farm animals such as poultry, rabbit, cattle, goats and pigs. It causes severe economic loss due to its symptoms that range from primary local infection to fatal septicemia. Pasteurella multocida is the responsible pathogen for this contagious disease. Chemotherapeutic treatment of Pasteurella is expensive, lengthy, and ineffective due to the increasing antibiotics resistance of the bacterium, as well as its toxicity to human consumers. Though, biosecurity measures played a role in diminishing the spread of the pathogen, the immunization methods were always the most potent preventive measures. Since the early 1950s, several trials for constructing and formulating effective vaccines were followed. This up-to-date review classifies and documents such trials. A section is devoted to discussing each group benefits and defects.

Development of a new trend conjugate vaccine for the prevention of Klebsiella pneumoniae.

Klebsiella pneumoniae is a major cause of nosocomial pneumonia, septicemia and urinary tract infections, especially in newborns, blood cancer patients, and other immunocompromised candidates. The control of K. pneumoniae is a complicated issue due to its tight pathogenesis. Immuno-prophylactic preparations, especially those directed toward the bacterium O-antigen, showed to be the most successful way to prevent the infection incidence. However, all previously proposed preparations were either of limited spectrum or non-maternal, and hence not targeting the main Klebsiella patients. Moreover, all preparations were directed only to prevent the respiratory diseases due to that pathogen. This article addresses the development of a method originally used to purify the non-capsular bacterial-endotoxins, as a new and easy method for vaccine production against K. pneumoniae. The application of this method was preceded by a biotechnological control of capsular polysaccharide production in K. pneumoniae. The new produced natural conjugate between the bacterial O-antigen and its outer membrane proteins was evaluated by physicochemical and immunological methods to investigate its purity, integrity, safety and immunogenicity. It showed to be pure, stable, safe for use, and able to elicit a protective immunoglobulin titer against different Klebsiella infections. This immune-response proved to be transferable to the offspring of the vaccinated experimental rabbits via placenta.

Development of immunization trials against Klebsiella pneumoniae.

Klebsiella pneumoniae is the most common cause of nosocomial respiratory tract and premature intensive care infections, and the second most frequent cause of Gram-negative bacteraemia and urinary tract infections. Drug resistant isolates remain an important hospital-acquired bacterial pathogen, add significantly to hospital stays, and are especially problematic in high impact medical areas such as intensive care units. Many investigations worldwide proved the increasing resistance of such pathogen, resulting in an average rate of 1.63 outbreak every year. A variety of preventive measures were applied to reduce such incidences. Immunotherapy and passive immunization researches as well found their way to the treatment of Klebsiella. During the last 40 years, many trials for constructing effective vaccines were followed. This up-to-date review classifies such trials and documents them in a progressive way. A following comment discusses each group benefits and defects.

Activation-induced apoptosis in peripheral blood mononuclear cells during hepatosplenic Schistosoma mansoni infections.

It is well established that programmed cell death (apoptosis) is an important regulator of host responses during infection with a variety of intra- and extra-cellular pathogens. The present work aimed at assessment of in vitro spontaneous and phytohemagglutinin (PHA)-induced apoptosis in mononuclear cells isolated from patients with hepatosplenic form of S. mansoni infections. Cell death data were correlated to the degree of lymphoproliferative responses to PHA as well as to the serum anti-schistosomal antibody titers. A markedly significant increase in PHA-induced apoptosis in lymphocytes isolated from S. mansoni-infected patients was seen when compared to the corresponding healthy controls. However, a slight difference was recorded between the two studied groups regarding the spontaneous apoptosis. This was accompanied with a significant impairment of in vitro PHA-induced lymphoproliferation of T cells from S. mansoni patients. Data of the present study supports the hypothesis that activation-induced cell death (AICD) is a potentially contributing factor in T helper (Th) cell regulation during chronic stages of schistosomiasis, which represents a critically determinant factor in the host-parasite interaction and might influence the destiny of parasitic infections either towards establishment of chronic infection or towards host death.

Immunological abnormalities in workers exposed to pollutants at an Egyptian copper company.

In the present work we studied: (a) biochemical changes; (b) serum immunoglobulins (IGs); and (c) mitogenecity of peripheral blood lymphocytes (PBL) in workers directly exposed to high concentrations of pollutants in several sectors of a major copper company in Alexandria. These sectors included the aluminum utensils refining of copper semicontinuous aluminum casting, brass foundries, and steel furnaces. Toxicants in these sectors included aluminum, hexachloroethan, silica, cadmium, copper, mercury, lead, abestos, nickels, zinc, silver, carbon iron, and sulfate present in high concentrations in the sectors where workers are directly exposed. Administrative personnel (indirectly exposed) were included as positive controls; negative controls were people living in areas of Alexandria where the concentrations of these toxicants are extremely low. All personnel of the aluminum utensils area showed reduction in serum levels of IgG, IgA, and IgM assayed by enzyme-linked immunosorbent assay (ELISA) while workers directly exposed in the other sectors showed elevated Igs. Mitogenic activity in cultured PBL assayed by 3H-thymidine uptake was impaired in all plant personnel. However, experimentals showed increases in the interleukins IL-2, IL-4, IL-6, interferon-gamma (IFN-gamma), tumour necrosis factor-alpha and-beta (TNF-alpha and beta) assayed by ELISA. Changes were directly related to duration of exposure. Some workers showed autoimmune symptoms such as arthritis and spondylitis. Allergic manifestations were also recorded. Thus, abnormalities were greatest in directly exposed workers, while other plant personnel showed some form of toxicity in the parameters studied. Clinical significance of the immunologic abnormalities seen is under further study.