Periplaneta americana Arginine Kinase as a Major Cockroach Allergen among Thai Patients with Major Cockroach Allergies

Periplaneta americana is the predominant cockroach (CR) species and a major source of indoor allergens in Thailand. Nevertheless, data on the nature and molecular characteristics of its allergenic components are rare. We conducted this study to identify and characterize the P. americana allergenic protein. A random heptapeptide phage display library and monoclonal antibody (MAb) specific to a the P. americana component previously shown to be an allergenic molecule were used to identify the MAb-bound mimotope and its phylogenic distribution. Two-dimensional gel electrophoresis, liquid chromatography, mass spectrometry, peptide mass fingerprinting, and BLAST search were used to identify the P. americana protein containing the MAb-specific epitope. We studied the allergenicity of the native protein using sera of CR-allergic Thai patients in immunoassays. The mimotope peptide that bound to the MAb specific to P. americana was LTPCRNK. The peptide has an 83–100% identity with proteins of Anopheles gambiae, notch homolog scalloped wings of Lucilia cuprina, delta protein of Apis mellifera; neu5Ac synthase and tyrosine phosphatase of Drosophila melanogaster, and a putative protein of Drosophila pseudoobscura. This finding implies that the mimotope-containing molecule of P. americana is a pan-insect protein. The MAb-bound protein of P. americana was shown to be arginine kinase that reacted to IgE in the sera of all of the CR-allergic Thai patients by immunoblotting, implying its high allergenicity. In conclusion, our results revealed that P. americana arginine kinase is a pan-insect protein and a major CR allergen for CR-allergic Thai patients

Specificity of immunoblotting analyses in eosinophilic meningitis

Angiostrongylus cantonensis and Gnathostoma spinigerum are the two most common causative parasites of eosinophilic meningitis (EOM). Serological tests are helpful tools for confirming the identity of the pathogen. Recent reports determined the specificity of such tests by using normal healthy controls. There have been limited studies done to rule out the cross-reactivity between these two causative parasites of EOM. This study aims to assess the specificity of the serological test in EOM by using each condition as a control for the other. Thirty-three patients with a diagnosis of EOM were enrolled. Sera from 22 patients with a positive 29-kDa antigenic diagnostic band of A. cantonensis were tested for the 21 and 24-kDa antigenic bands of G. spinigerum. Similarly, sera of 11 gnathostomiasis patients were tested for the 29-kDa diagnostic band for A. cantonensis. Only one patient in the angiostrongyliasis group had a positive result for the 21 and 24-kDa antigenic bands of G. spinigerum, while no gnathostomiasis patients showed a positive result for the 29-kDa antigenic band of A. cantonensis. The specificity of the 21 and 24-kDa antigenic bands for gnathostomiasis and the 29-kDa antigenic band for A. cantonensis was 95.5% and 100%, respectively. The antigenic bands for the diagnosis of gnathostomiasis and angiostrongyliasis in EOM were highly specific

Serum and secretory antibody responses to Neisseria gonorrhoeae in patients with gonococcal infections.

The present study was conducted to characterize the nature and pattern of serum and secretory antibody responses to N. gonorrhoeae by haemagglutination inhibition, opsonization, and immunofluorescence techniques in male and female patients with different clinical manifestations of gonorrhoea. Most male patients with acute gonococcal infection developed serum IgG and, less frequently, IgM antibodies against pilated gonococci within 2 weeks of infection and these antibodies declined to normal levels 1 to 2 months after treatment. This response was not noticeably different from the responses developed in male patients with subacute infection and female patients with chronic infection. Immunological analyses of the seminal plasmas and cervical fluids from these patients showed that antibodies reactive with both pilated and non-pilated N. gonorrhoeae are present in some of the cases. A small percentage of male patients who recovered from subacute gonococcal infection but not from acute infection possessed low levels of IgG and, less frequently, IgA antibodies to gonococcal antigens in their seminal plasmas. In contrast, more than half of the females with gonorrhoea had IgG antigonococcal antibodies in the cervical fluid. However, a small number of samples also showed the presence of IgA and IgM antibodies. IgA antibody in most of these IgA-positive samples was of the secretory type. The presence of secretory IgA (SIgA) in secretions and the lack of correlation between the antibody titres in serum and in secretions of these patients suggest that infection with N. gonorrhoeae may independently stimulate both a systemic and a local humoral immune response

Detection with monoclonal antibody of Salmonella typhi antigen 9 in specimens from patients

Monoclonal antibodies were raised against Barber antigen (Ba) of Salmonella typhi 0901. Antibodies produced to antigen 9 of group D salmonellae were used in double- and triple-sandwich antibody enzyme-linked immunosorbent assays (ELISAs) for detecting antigen 9 in urine and plasma specimens from three groups of patients and 49 controls. The triple-antibody ELISA detected the antigen in urine samples from 11 of 18 (65%) patients with hemoculture-proven typhoid (group 1) and 12 of 39 (31%) patients with clinical features compatible with typhoid but whose hemocultures were negative (group 2). This ELISA was negative in three patients from whom Salmonella paratyphi A, Escherichia coli, and Klebsiella pneumoniae (group 3) were isolated by hemoculture and in all healthy controls. The double-antibody sandwich ELISA was positive in 41 and 15% of urine samples from patients in groups 1 and 2, respectively, and was negative with samples from two patients from group 3 and all controls. The sensitivity and specificity compared with those for healthy controls were 65 and 100%, respectively, for the triple-antibody ELISA. Although as little as 7.8 ng of homologous lipopolysaccharide could be detected, background in clinical specimens prevented accurate interpretation of the detection of this antigen in serum. Results were best with urine specimens.</jats:p

Circumsporozoite proteins of human malaria parasites Plasmodium falciparum and Plasmodium vivax

The malaria sporozoite injected into a host by the bite of the mosquito vector initiates the parasite cycle that culminates in clinical disease. This sporozoite stage is highly antigenic, and immunization with irradiated sporozoites has prevented the development of malaria in rodent and simian hosts as well as in several human volunteers (1). Antisporozoite antibodies detectable in the sera of the immunized primate hosts appear to be associated with immune resistance. Recently, hybridoma-derived monoclonal antibodies directed against sporozoites of rodent and simian malaria were found to be protective, i.e., to abolish sporozoite infectivity both in vivo (2) and in vitro (3). 1 These antibodies react with circumsporozoite (CS) 2 proteins; that is, stage- and species-specific polypeptides that are uniformly distributed over the entire surface of the parasite and that are shed when cross-linked by antibodies (2, 4). 1 The hybridoma technique was therefore used to develop monoclonal antibodies against sporozoites of P falciparum and P. vivax in an attempt to identify the protective antigens of the human pathogens for their application in a vaccine