Everyone should by now have received Bob Gallo's formal proposal for the use of HTLV-3/LAV or LAV/HTLV-3 as the name of
the causative agent of AIDS. In case you have not, I enclose a copy of it, as well as a copy of his letter of February 5,
which some of you have not received.
I am writing to request that you respond promptly by express mail to Bob's proposal, using the attached form to indicate
your views. I believe that the considerable correspondence we have had over the past year includes virtually all of the arguments
to be made for and against this proposal, so I will not reiterate them here. But I urge each of you to review past materials
and give careful thought to what I hope will serve as a final verdict on this important question.
I do feel obliged to comment briefly upon the two points about the name human immunodeficiency virus (HIV) raised in the final
paragraph of Bob's recent letter. His comments address the speculative problems implicit in the pathogenetically-based
nomenclature that retrovirologists (among others) have traditionally used: how to differentiate genetically different viruses
that happen to cause the same or similar diseases and how to designate genetically highly related viruses that differ in pathological
potential. (Note that parallel concerns afflict nomenclature based upon cell tropism: how to differentiate genetically distinct
viruses that happen to exhibit tropism for the same cell type, perhaps even using different receptors in the same cell, and
how to designate genetically similar viruses that appear to differ in tropism.)
(i) Future virus isolates, unrelated to the cause of AIDS but inducers of immunodeficiency of any type, would be given names
other than HIV, even if they are retroviruses. I share Bob's previously stated faith in the retentive powers of medical
students and practitioners, so I believe that the link between HIV and AIDS would become quickly and unambiguously established.
As for distinguishing between T and B cell immunodeficiency, the term "AIDS" does not refer to T cells, and I don't
think it is necessary for the name of the virus to do so either.
(ii) Future virus isolates, partially related to the AIDS virus but apparently non-pathogenic, would probably be dealt with
in the following manner, based upon my consultations with several of you. Viruses very highly related to the prototypes (e.g.
over 50% nucleotide sequence identity) should be called substrains of HIV; it is quite possible that already existing isolates,
particularly from healthy high-risk populations, will prove to meet these criteria. Viruses clearly different on molecular
grounds (e.g. less than 20% nucleotide sequence identity) present only the problem of finding an appropriate new name. I
agree with Bob that any demonstrably non-pathogenic viruses in the grey area (e.g. 20-50% nucleotide sequence identity) should
also be given new names, once their characteristics have been thoroughly studied. (Until we know the appropriate genetic
and biological facts about the recent isolates from Max Essex's lab mentioned in Bob's letter, I do not think it is
proper for me to comment upon final names for them.) If we should ultimately agree upon the previously circulated letter
in favor of HIV, I would propose to add a final point on this issue as follows: "(vii) Any future isolates of human retroviruses
with clear but limited relationship to isolates of HIV (e.g. more than 20% but less than 50% nucleic acid identity) should
not be called HIV unless there are compelling biological similarities to existing members of the group.
Finally, the lesson I think we have all learned from our extended exercise in nomenclature is that no name is perfect and
that we should aim to settle upon one that raises the fewest and least severe objections. With this objective in mind, I
hope that we can show a sometimes skeptical public that, despite unresolved differences of opinion, we can come to an amicable
agreement that fosters easy communication among us. Thus, though my own preferences are clear, I am prepared to sign and
advertise whatever agreement gathers the most support. In hopes that all of us who agreed to deliberate on this trying matter
will now agree to support the resolution we reach, I have phrased the attached form to learn about preferences rather than
opposition. Please return it to me today.