Intra-articular antigen-antibody reactions

The role of humoral immune mechanisms in the induction, maintenance, and modulation of chronic arthritis in the two main tissues of diarthrodial joints synovial membrane and cartilage is discussed. In the synovial membrane of patients with RA, the available data suggest that there is a selective enrichment of immunoglobulin-secreting cells with restricted specificities. However, it is likely that the B-lymphocyte lineages infiltrating the synovial membranes are not self supporting and autonomous but that they originate from precursors activated and released from the central lymphoid organs. The processes leading to irreversible destruction of articular cartilage in chronic arthritis are not well understood. A review of the possible pathogenic role of immunoglobulin and immune complexes tightly bound to the superficial layers of cartilage suggests that these contribute to the chronicity and severity of the inflammatory process. However, accurate evaluation of the relative importance of these mechanisms can only be attained when more information becomes available on the interplay between cellular and humoral immune mechanisms within the joint.     

Aplasia of submandibular salivary glands associated with ectodermal dysplasia.

We describe a 28-year-old white Caucasian man displaying many of the physical signs of ectodermal dysplasia (ED). An unusual finding was his presentation with xerostomia. Salivary gland imaging techniques revealed aplasia of both submandibular salivary glands and relatively small parotids. The case highlights that hypoplasia and aplasia of exocrine glands could be rare features of ED. In the management of ED, early detection of xerostomia is important to limit any potential damage to the already hypodontic dentition.     

Identification and genomic localization of a pseudorabies glycoprotein via expression in Escherichia coli

A glycoprotein (gp-88) secreted by pseudorabies virus (PRV) infected cells was isolated and purified. Anti gp-88 antibodies were used to screen an expression library constructed in Escherichia coli using genomic PRV DNA. Two positive clones were identified and the cloned genetic information was used to localize the corresponding gene in the unique short region of the PRV genome. Antibodies to the glycoprotein were also used to identify the unglycosylated precursor as synthesized in an in vitro translation system. A major precursor of 65 kDa was detected. Although the glycoprotein described here was not found as a major structural glycoprotein of the virion, antibodies to gp-88 are able to neutralise viral activity in vitro. The possible relationship with known glycoproteins of PRV is discussed.     

Infective endocarditis due to Salmonella typhi--a case report

Endocarditis is a rare complication of typhoid fever. We report a case in which Salmonella enterica serotype typhi was isolated from a case of endocarditis. The isolate was resistant to ampicillin, chloramphenicol and ciprofloxacin but sensitive to ceftriaxone, amikacin and gentamicin.     

Humoral immune responses of Brucella-infected cattle, sheep, and goats to eight purified recombinant Brucella proteins in an indirect enzyme-linked immunosorbent assay.

Brucellosis research is currently focused on the identification of nonlipopolysaccharide (LPS) antigens which could potentially be useful for the specific serologic diagnosis of brucellosis as well as for vaccinal prophylaxis. On the basis of previous reports, we selected eight Brucella proteins (OMP36, OMP25, OMP19, OMP16, OMP10, p17, p15, and p39) as candidate antigens to be further evaluated. The genes encoding these proteins were cloned, sequenced, and overexpressed in Escherichia coli. The recombinant proteins were purified with a polyhistidine tag and metal chelate affinity chromatography and evaluated in an indirect enzyme-linked immunosorbent assay (iELISA). The specificity of the iELISA was determined with sera from healthy cattle, sheep, and goats and ranged from 95 to 99%, depending on the recombinant antigen and the species tested. Sera from experimentally infected, and from naturally infected, animals were used to evaluate the sensitivity of the iELISA. The antiprotein antibody response was often delayed when compared to the anti-smooth LPS (S-LPS) response and was limited to animals which developed an active brucellosis infection (experimentally infected pregnant animals and sheep and goats from areas where brucellosis is still endemic). Among the recombinant antigens, the three cytoplasmic proteins (p17, p15, and p39) gave the most useful results. More than 80% of the animals positive in S-LPS serology were also positive with one of these cytoplasmic proteins alone or a combination of two of them. None of the recombinant antigens detected experimentally infected nonpregnant cows and sheep or naturally infected cattle. This study is a first step towards the development of a multiprotein diagnostic reagent for brucellosis.     

Detection and subtyping of HIV-1 isolates with a panel of characterized monoclonal antibodies to HIV p24gag

A panel of monoclonal antibodies (Mabs) was used to analyze the number and localization of B-cell epitopes on human immunodeficiency virus (HIV) p24gag and the variability of these epitopes in sequential HIV isolates and in isolates from different geographical origin. The specificity of these Mabs was demonstrated by immunoblotting and radioimmunoprecipitation assays. Cross-inhibition experiments indicated the presence of at least five different epitopes on p24. Analysis with p24 recombinant products revealed that three of the Mabs to p24 were directed to epitopes localized on the C-terminal part. Four other Mabs were directed to epitopes localized on the N-terminal half of the protein. Anti-p24 Mabs were used to develop HIV p24 antigen-capture assays. Application of these assays in HIV isolation resulted in more efficient recovery of HIV. Serotyping of HIV-1 isolates with five anti-p24 Mabs demonstrated that 55/65 isolates recovered from Dutch and Belgian individuals, but only 4/9 HIV-1 African isolates, were recognized by all five Mabs. Five of nine Central African HIV-1 isolates were not reactive with at least one of these Mabs. The variability of p24 appeared to be predominantly localized on the N-terminal part of the protein. Lack of expression of antigenic determinants on p24 was shown to be independent of culture conditions. Moreover, an infectious molecular clone was shown to have the same serotype as the corresponding HIV isolate. The serotype of sequential isolates obtained from 17 individuals over a 1 1/2- to 2 1/2-year period did not change, suggesting a limited in vivo p24 variation over time.     

The antigenicity of some synthetic poly-iminoacids: I. Antigenic properties of poly-L-proline

The antigenic properties of a group of synthetic poly-iminoacids have been tested in guinea-pigs and rabbits by active cutaneous anaphylaxis, delayed skin hypersensitivity reactions, passive cutaneous anaphylaxis, (PCA), tanned cell agglutination and agglutination-inhibition. The antigenicity of a linear homopolymer, poly-L-proline, has been demonstrated in guinea-pigs. This polymer exists in two forms differing only in their secondary structure, Form I having a right-handed helix and Form II a left-handed helix. That both forms are antigenic and yet non-cross-reacting emphasizes the importance of secondary structure in this system.Comparison of polyprolines of different molecular weights suggests the presence of more than one antigenic determinant; a polymer of an average molecular weight of 1500 was antigenically deficient compared with a polyproline of a molecular weight of 17,000.No cross-reactions were detected between anti-polyproline or anti-polyproline-glycine and collagen or its derivatives.The possible structure of the antigenic determinants involved is discussed.     

Employment Consequences of COVID-19 for People with Disabilities and Employers

Journal of Occupational Rehabilitation - Purpose The COVID-19 pandemic has disproportionately affected the lives of people with disabilities (PWD). How the pandemic affects the employment of PWD...     

Job Accommodations,Return to Work and Job Retention of People with Physical Disabilities: A Systematic Review

Journal of Occupational Rehabilitation - Purpose We aimed to identify job accommodations that help persons with physical disabilities maintain or return to work and explore the barriers and...