Circumsporozoite protein of Plasmodium gallinaceum characterized by monoclonal antibodies

Monoclonal antibodies (MoAb) were produced against both salivary gland sporozoites (SGS) and oocyst sporozoites (OS) of Plasmodium gallinaceum, an avian malaria parasite. By indirect immunofluorescence, all of the MoAbs reacted with both SGS and OS of P. gallinaceum and two of the MoAbs cross-reacted weakly with P. berghei sporozoites. None of the MoAbs reacted with sporozoites of six additional species of mammalian plasmodia. In Western blot analysis of extracts of either SGS or OS of P. gallinaceum, these MoAbs identified two polypeptides with molecular weights of approximately 76,000 and 64,000 D. The results of a MoAb inhibition of binding assay and a two-site one-antibody immunoradiometric assay indicate that the circumsporozoite protein of P. gallinaceum, like those of mammalian malaria parasites, contains a repetitive immunodominant epitope. Two of the anti-P. gallinaceum MoAbs were tested in a sporozoite neutralization assay and decreased, but did not abolish, the infectivity of sporozoites for chickens, indicating that the polypeptide of P. gallinaceum identified by immunoblot is probably the protective antigen.     

Retrograde catheterization of left ventricle through mechanical aortic prostheses

Twenty-three patients who had undergone aortic valve replacementwith a mechanical aortic vlave prosthesis (ball-valve: 17, tilting-disc:6) were investigated by retrograde left ventricular catheterizationusing a 6 F pigtail catheter. Tweleve of these 23 patients alsohad combined aortic and mitral valve replacement. To assessthe magnitude of the catheter-induced aortic regurgitation andits effect on left ventricular and mitral valve function, 10patients (group 1) were simultaneously investigated by the transseptalroute (8 patients) or direct left ventricular puncture. The13 other patients (group 2) were studied only by the retrogradecrossing of the aortic valve prosthesis. In group 1, placementof the catheter across the valve induced an increase in heartrate (+ 12%), in left ventricular end-diastolic pressure (from17.2±9.6 to 33.3±12.0 mmHg), a decrease om aorticsystolic (–19%) and diastolic (–25%) pressures,and left ventricular systolic pressure (–10%). Transvalvularaortic pressure gradient increased from 15.4±8.2 to 23±12.1mmHg. Pre- and post-crossing pressure gradients were linearlycorrelated (r=0.98). Hence, the magnitude of catheter-inducedaortic regurgitation averaged 27% whether or not a pre-crossingregurgitation was noted. In group 2, retrograde crossing ofthe aortic valve prosthesis induced similar hemodynamic changes.There were no catheterization-related complications.On the basisof catheterizations studies, re-operation was contraindicatedin 2 patients because of severe left ventricular depression,and recommended in 18: aortic valve dysfunction in 14 patients,mitral valve incompetence in 4 patients. In 3 patients, thehemodynamic study ruled out any aortic valve prosthesis dysfunction,associated mitral valve disease and depressed left ventricularfunction. Intraoperative findings (15 patients) and postmortemexamination (7 patients) were consistent with catheterizationdata. Left ventricular retrograde catheterization is an alternativetechnique of investigation for patients with mechanical valvesin both mitral and aortic positions or in centers where theusual approach (transseptal catheterization or direct LV puncture)are not performed.     

Molecular analysis of HLA DR4-/β1 gene in malaria vaccinees. Typing and subtyping by PCR technique and oligonucleotides

The combination of the PCR technique and the synthetic oligonucleotides has proved to be a useful tool in the molecular analysis of HLA class II genes, allowing recognition of as little as a single nucleotide modification in the sequence of the gene. The molecules encoded by these genes have been associated with genetic control of the immune response and with susceptibility to certain diseases. Studies carried out in our laboratory have shown three patterns of humoral immune response in the human volunteers vaccinated with the synthetic protein SPf 66; high, intermediate and low responders. Approximately 73.3% of the low responders were serologically typed as HLA DR4 and 42% as DQw6. These results moved us to look for a subtype (Dw) correlation between the DR4 positive individuals and the different humoral immune response patterns. Using oligo-typing methods after previous amplification of the DR4 B1 exon, we subtyped 20 DR4 volunteers, classified as high, intermediate and low responders. We did not find any direct association between the HLA DR4 Dw special subtype in the high or low responders immunized with the SPf 66 vaccine.