RESUMO
We have measured the asymmetric emission of protons from the nonmesonic decay of polarized (5)(Lambda)He produced by the (pi(+), K+) reaction. (5)(Lambda)He is an s-shell hypernucleus and its polarization is due to the Lambda. One expects to obtain direct information on the elementary weak Lambda-->p-->np process. The asymmetry parameter has been determined to be 0.24+/-0.22. The implication of the result is discussed.
RESUMO
The [Tyr5,12,Lys7]-polyphemusin II peptide (T22) inhibits HIV-1 replication in lymphocytes. The mechanism of T22 inhibition of HIV-1 replication may involve T22 competition with HIV-1 for attachment sites on the plasma membrane of targeted cells. Here we find that the T22 peptide binds to the CD4 molecule in affinity columns. We also find that antiserum to CD4 inhibits cell attachment to T22. Further CD4+ transfected cells attach to T22 while their parental cells which do not express CD4 do not attach to T22. These data demonstrate that T22 binds to the CD4 molecule and supports the hypothesis that T22 inhibits HIV-1 replication by binding to the cell surface CD4 molecule and inhibiting uptake of the virus.
Assuntos
Antígenos CD/fisiologia , Peptídeos Catiônicos Antimicrobianos , Antivirais/metabolismo , Antígenos CD4/fisiologia , HIV-1/fisiologia , Peptídeos/metabolismo , Sequência de Aminoácidos , Antígenos CD/isolamento & purificação , Antivirais/química , Antivirais/farmacologia , Sítios de Ligação , Ligação Competitiva , Antígenos CD4/isolamento & purificação , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Cromatografia de Afinidade , HIV-1/efeitos dos fármacos , Células HeLa , Humanos , Cinética , Dados de Sequência Molecular , Peptídeos/química , Peptídeos/farmacologia , Conformação Proteica , Replicação Viral/efeitos dos fármacosRESUMO
The [Tyr5,12,Lys7]-polyphemusin II peptide (T22) has been shown to inhibit HIV-1 replication in lymphocytes. The mechanism of T22 inhibition of HIV-1 replication is not known but may involve T22 competition with HIV-1 for attachment sites on the plasma membrane of targeted cells. Here we find that three human immunocyte cell lines (H9, Jurkat, and U-937) attach to T22. The phorbol ester, 12-O-tetradecanoylphorbol 13-acetate (TPA), has been shown to activate intracellular protein kinase C and to stimulate lymphocyte attachment to various substrates through specific cell surface receptors. Here we find that TPA treatment enhances attachment of the immunocytes to T22 by three- to four-fold. These data demonstrate that T22 binds to immunocyte cell surfaces and support the hypothesis that T22 may inhibit HIV-1 replication by competing with the virus for a common cell surface receptor(s).
