A chimera of the two immunodominant African swine fever (ASF) virus proteins p54 and p30 was constructed by insertion of the gene CP204L into a Not I restriction site of E183L gene. The resulting chimeric protein p54/...
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A chimera of the two immunodominant African swine fever (ASF) virus proteins p54 and p30 was constructed by insertion of the gene CP204L into a Not I restriction site of E183L gene. The resulting chimeric protein p54/30, expressed by a recombinant baculovirus in insect cells and in Trichoplusia ni larvae, retained antigenic determinants present in both proteins and reacted in Western blot with a collection of sera from inapparent ASF virus carrier pigs. Remarkably, pigs immunized with the chimeric protein developed neutralizing antibodies and survived the challenge with a virulent African swine fever virus, presenting a reduction of about two logs in maximum viremia titers with respect to control pigs. In conclusion, this study revealed that the constructed chimeric protein may have utility as a serological diagnostic reagent and for further immunological studies that may provide new insights on mechanisms of protective immunity to ASFV.
OBJECTIVES Our study attempted to gain further understanding of the allosteric effects of human autoantibodies on beta(1)-adrenergic receptor (beta(1)-AR) function. BACKGROUND Recently, we reported on the existence of...
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OBJECTIVES Our study attempted to gain further understanding of the allosteric effects of human autoantibodies on beta(1)-adrenergic receptor (beta(1)-AR) function. BACKGROUND Recently, we reported on the existence of activating anti-beta(1)-AR antibodies in patients with dilated cardiomyopathy (DCM 26% prevalence) or ischemic cardiomyopathy (ICM, 10% prevalence);however, their functional effects have not yet been thoroughly characterized. METHODS In this study we detected functionally active receptor-antibodies in 8 out of 30 DCM patients. Their immunological and functional properties were analyzed using both synthetic receptor-peptides and intact recombinant human beta(1)-AR, and were compared with those of heterologous antibodies to selected beta(1)-AR domains generated in rabbits and mice. RESULTS Rabbit, mouse, and human anti-beta(1)-AR against the second extracellular domain preferentially bound to a native receptor conformation and impaired radioligand binding to the receptor. However, their functional effects differed considerably: Rabbit and mouse antibodies decreased both basal and agonist-stimulated cAMP production, whereas the patient antibodies (n = 8) increased basal, and six of them also increased agonist-stimulated receptor activity (i.e., acted as receptor-sensitizing agents). Two out of eight human anti-beta(1)-AR increased basal but decreased agonist-stimulated receptor activity (i.e., acted as partial agonists). CONCLUSIONS Antibodies against the same small beta(1)-AR domain can have very divergent allosteric effects, ranging from inhibitory to agonist-promoting activities. Activating autoantibodies were associated with severe cardiac dysfunction and thus might be involved in the development and/or course of human cardiomyopathy. (J Am Coll Cardiol 2000;36:1280-7) (C) 2000 by the American College of Cardiology.
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