AIDS RESEARCHVolume 1, Number 6, 1984/5Mary Ann Liebert. Inc.. PublishersPp. 455-457

AIDS-RELATED ABSTRACTS FROM THE FIFTHANNUAL CONGRESS FOR RECOMBINANT

DNA RESEARCH

THE FAMILY OF HUMAN LYMPHOTROPIC RETROVIRUSES CALLED HTLV: HTLV-ICAUSES ATL, HTLV-II MAY CAUSE SOME HAIRY CELL LEUKEMIAS, ANDHTLV-III CAUSES AIDS, Robert C. Gallo, Laboratory of Tumor CellBiology, National Cancer Institute, Bethesda, Maryland 20205,

HTLV is the generic name we gave to the first and all subse¬quently discovered human retroviruses. Since the initial ident¬ification of HTLV-type I in sporadic cases of adult T-cell malig¬nancies in the U.S., well over 100 isolates of viruses belongingto this HTLV family have been described worldwide. Theseviruses, which have now been linked to the pathogenesis of adultT-cell leukemia (HTLV-I) and the acquired immunodeficiency syn¬drome or AIDS (HTLV-III), share the following biological andphysicochemical properties: (i) tropism for T-lymphocytes, (ii)a relatively small major core protein (p24), (iii) a high molecu¬lar weight Mg++ preferring reverse transcriptase, (iv) varyingdegrees of cytopathy as evidenced in vitro by the induction ofmultinucleated giant cells, (v) varying degrees of antigenic andnucleic acid sequence homology, and (vi) a likely African origin.The isolation of all types of HTLV (I, II, and III) has been maderoutine by the use of T-cell growth factor (TCGF), also known asinterleukin-2, and by the cultivation of the proper cell type.Using these techniques, we have isolated and characterized numer¬ous isolates of HTLV-I from the U.S., the Caribbean, Japan, Southand Central America, and Africa, as well as a closely relatedretrovirus from Old World monkeys. HTLV-I is involved in thepathogenesis of ATL. In collaboration with D. Golde, we alsoisolated HTLV-II from cultured cells of a young man with hairycell leukemia. Many properties of HTLV-II are similar to thevarious isolates of HTLV-I including the ability to immortalizenewly infected T-cells in vitro, but major differences in theirgenomes nonetheless exist. In February 1982 we first proposedthe idea that a T-lymphotropic human retrovirus could cause AIDS.Using the same culture techniques which were used to identify thefirst human retrovirus (HTLV-I), we obtained 96 isolates of anovel T-lymphotropic retrovirus (HTLV-III) from patients withAIDS or AIDS-related complex (ARC) . The same approach was usedby Barre-Sinoussi et al_. in their first identification of virusin a lymphadenopathy" patient. We have detected anti-HTLV-IIIantibodies in 288/297 (97%) AIDS patients, 327/360 (9U) ARCpatients, 19/19 (100%) of blood transfusion associated AIDS, andin 96/235 (41%) asymptomatic homosexual men in contrast to noneof 879 normal heterosexuals. These data, along with the demon¬strated T-lymphocyte tropism and cytopathic effects of the virus,led us to conclude that HTLV-III is the causative agent of AIDS.In collaboration with J. Groopman and D. Zagury we also recentlyreported the isolation of HTLV-III from saliva and semen, inaddition to blood, lymph node, bone marrow and spleen, and havemolecularly cloned the complete viral genome. The implicationsof these studies involving the HTLV family of viruses and someideas for future work will be discussed.

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456 ABSTRACTS

A RECOMBINANT DNA PRODUCED PEPTIDE OF HTLV-IIIWHICH IS IMMUNOREACTIVE WITH SERA FROM AIDS PATIENTS.James J. Huang, John Ghrayeb, Sam McKinney, Tse Wen Chang,and Nancy T. Chang, Centocor, Inc., 244 Great Valley Parkway,Maivern, PA 19355.

Human cell lymphotrophic retrovirus type-Ill (HTLV-III)has been identified as the etiological agent of AcquiredImmunodeficiency Syndrome (AIDS). Recent establishment of apermissive cell line for HTLV-III propagation led to theisolation, molecular cloning and analysis of the virus. DNAsequence analysis of the HTLV-III viral genome has just beencompleted. This data revealed that some distant sequencehomology exists between HTLV-III and HTLV-I and -IIconsistent with the result of earlier hybridization studies.The overall structure of the provirus resembles that of otherretrovirus. The provi ral genome is flanked at both ends bylong terminal repeated (LTR) sequences. Four long openreading frames (ORF) are identified within the viral DNA. Inthis report we studied the synthesis of various viralpeptides by constructing bacterial expression plasmids thatcontained cloned segments of HTLV-III genome. The 1.1 KbEcoRI DNA fragment, which includes 3' end of the poi gene anda short open reading frame (SOR), was inserted into E^. colisecretion vectors pIN-III-ompA. E. coli transformantscontaining the recombinant plasmid, 01R6, produced a 15 Kdprotein that reacts strongly with sera from AIDS patients.The identity of the 15 Kd peptide was studied using animmunoinhibition assay. The immunoreaction between the viralp31 protein and anti-p31 antibody present in sera of AIDSpatients can be inhibited by lysates of £. coli (01R6)cells. This pi5 peptide was used to screen a panel of 28serum samples consisting of AIDS patients and normalindividuals. The peptide reacted with sera of 20 AIDSpatients and none of the normal controls and thus may beuseful in the development of a diagnostic test for screeningblood and blood products.

ABSTRACTS 457

MOLECULAR CHARACTERIZATION OF AIDS RELATED RETROVIRUSES

D. Dina*, . Steimer*, R. Sánchez-Pescador*, M. Power*,M. Stempien*, P. Barr*, J. Levy**, and P. Luciw*. *ChironResearch Laboratories, Chiron Corporation, Emeryville,California and **Cancer Research Institute, Department ofMedicine, University of California, San Francisco, California.

AIDS (Acquired Immune Deficiency Syndrome) is a recentlyrecognized human disease presumably caused by a retroviralinfection. The disease leads to collapse of the immune systemand results in death by opportunistic infections and isassociated with unusual forms of neoplasia. The RNA genome andDNA forms of an AIDS associated retrovirus (ARV) have beencharacterized. ARV DNA has been molecularly cloned and itsnucleotide sequence determined. The DNA genome is 9739 basepairs long and encodes long terminal repeats and open readingframes coding for retroviral genes (gag, pol, and env) involvedin viral replication. Three small open reading frames (100-200codons) of unknown biological significance were also identified.Several molecular clones from the same ARV isolate were sequencedand polymorphisms were observed. Polymorphism of restrictionenzyme sites was observed among ARV isolates obtained fromdifferent patients. Synthetic peptides representing specificregions of ARV proteins are being used (1) to assess immuneresponses in AIDS patients and (2) to raise antisera in animals.These specific sera will allow us to evaluate the extent ofpolymorphism at the protein level in different virus isolates.