Production of monoclonal antibodies against serotype strains of Pseudomonas aeruginosa.

A panel of 22 monoclonal antibodies against 8 of the 17 International Antigenic Typing Scheme (IATS) serotypes of Pseudomonas aeruginosa was produced. The antibodies were characterized for cross-reactivities, isotypes, titers, and epitope specificities. The results complemented those of our previous study and marked the completion of a set of monoclonal antibodies for serotyping P. aeruginosa.     

Assay restriction profiles of three monoclonal antibodies recognizing the G3m(u) allotype. Development of an allotype specific assay

Three monoclonal antibodies raised against a purified human IgG3 paraprotein were found to exhibit a restriction profile for IgG3/G3m(u) and pan-IgG specificity which was dependent on the assay system. When adapted to an IgG3 subclass capture ELISA, all three McAbs discriminated between paraproteins expressing G3m(u) and antithetical markers G3m(st). One of the antibodies (PNF69C) was selected and conditions were optimised for Gm typing purposes. Using this system G3m(u) could be detected on captured IgG3 derived from human sera. This system may prove useful in the elucidation of Gm allotype profiles.     

IgE-dependent histamine-releasing factors. A brief review.

A cytokine, termed histamine-releasing factor (HRF) and produced by many cell types, has become the focus of research by many investigators due to its potential importance as a stimulus in chronic inflammation. We are producing and characterizing an HRF which causes IgE-mediated histamine release from human basophils. Following extensive purification procedures, the molecule will be sequenced and synthesized. A functional heterogeneity of IgE molecules was revealed by these studies. We are currently producing IgE antibody in vitro and testing the hypothesis that differential glycosylation is the basis for the heterogeneity. Knowledge of the structures and interactions of these molecules should advance our understanding of allergic and more chronic diseases.     

Growth and development in thanatophoric dysplasia

Two cases of prolonged survival of thanatophoric dysplasia are presented, in which ventilatory support was initiated in the neonatal period because of respiratory distress. Both patients required a ventriculoperitoneal shunt for hydrocephalus and had decompression of the posterior fossa. The history of each patient has been characterized by profound developmental delay and dramatic growth failure.     

Hypoplasia of the cerebellar vermis and corpus callosum in thrombocytopenia with absent radius syndrome on MRI studies

Thrombocytopenia with absent radius (TAR) syndrome is infrequently (7%) associated with mental retardation. In those cases, the mental deficiency is presumed to be a consequence of intracranial hemorrhage due to the thrombo-cytopenia. We report on 2 infants with TAR syndrome. One had developmental delay with evidence of cerebral dysgenesis by magnetic resonance imaging (MRI). Such findings have not been noted in the literature, but may not have been investigated in most cases. The other infant with TAR syndrome, who has had normal psychomotor development, has a normal brain on MRI scan. Detailed neuroimaging studies, preferably MRI, should be considered in the evaluation of patients with TAR syndrome, especially when there are documented signs of developmental delay, with or without a history of intracranial hemorrhage. © 1994 Wiley-Liss, Inc.     

Evaluation of Questor urine screening system for bacteriuria and pyuria.

AIMS--To evaluate the Questor automated bacteriuria and pyuria screening system; to compare its performance with that of a reference method; and to assess its usefulness in a routine clinical laboratory. METHODS--The Questor urine screening system was compared with a comprehensive regimen to detect urinary tract infection, using pour-plate viable counts to determine the numbers of bacteria present in urine samples, a wide range of other cultural methods, microscopic findings and clinical information. RESULTS--The optimal performance in detecting significant growths was a sensitivity of 93%, a specificity of 74%, a positive predictive value of 43% and a negative predictive value of 98%. The list price per test is 0.17 pounds and the capital cost of the system is 39,950 pounds. Questor can test 50 samples an hour and can be operated by one member of the laboratory staff, who is not required to make interpretative judgments--for example, a medical laboratory assistant. CONCLUSIONS--The sensitivity and specificity of the Questor was better than that obtained from other screening systems using the same protocol. The system was easy to use and is a useful addition to the methods available for screening for bacteriuria.     

Expression of the CD28 costimulatory molecule on subsets of murine intestinal intraepithelial lymphocytes correlates with lineage and responsiveness

The CD28 antigen has been recently demonstrated to be a costimulatory molecule and is expressed by almost all thymic and peripheral T cell receptor (TcR) α^δ+ and γ^λ+ cells in the mouse system. We show here that expression of CD28 is heterogeneous among murine intestinal intraepithelial lymphocytes (IEL). Whereas some TcR αβ-expressing IEL subsets such as CD4⁺8^? and CD4^?8α⁺β⁺ cells express CD28 at the same levels as their phenotypic counterparts in lymph node, other subsets of TcR αβ cells (including CD4^?8α⁺β^? and CD4⁺8αβ⁺β cells) as well as TcR γ^λ+ IEL fail to express CD28. Parallel experiments using aged BALB/c-nu/nu mice indicated that CD28 expression patterns among IEL are quite similar to those of normal BALB/c mice. Furthermore, forward light scatter analysis showed that CD28^? cells are considerably larger than CD28⁺ cells in the gut, although cycling cells were rare in both subsets. Finally CD28^? cells in the gut did not proliferate or produce IL-2 upon stimulation by anti-CD3 monoclonal antibodies (mAb) and phorbol 12-myristate 13-acetate, whereas CD28⁺ cells in the gut and lymph nodes responded to these stimuli. The response of the CD28⁺ cells was enhanced by anti-CD28 mAb. These results suggest that CD28^? IEL (CD4-8α⁺β^? cells, and some CD4⁺8α⁺β^?cells) may follow a different developmental pathway from that of CD28⁺ IEL in a thymus-independent environment, and that expression of CD28 correlates with responsiveness of the cells to triggering via the TcR-CD3 complex.