My name is Farshad Guirakhoo,
and I am Chief Technology Officer at Vaxess Technologies located
in Cambridge, Massachusetts.
I will be talking about replication
competent viral vectors.
I will be talking about virus
classification, infectious diseases
in humans caused by viruses, and vaccine approaches
to combat such diseases.
Next, I will focus on vaccines based
on viral vectors, general barriers
and challenges, then describe
and challenges for both
and replication-competent vectors.
The talk will be then
vectors, starting with describing
the rationale for this selections,
and going onto a few examples
of replication-competent vectors
which are either in clinical
development or already marketed.
These include VSV, or vesicular stomach virus,
or yellow fever-based replication-competent vectors.
A summary slide will conclude this presentation.
One may wonder how many viruses
are actually on the planet Earth.
The answer is, nobody
knows at this time.
But one estimate puts the number of viruses
in mammals at more than 320 thousand.
If one adds invertebrates, plants, mushrooms,
and Brown Algae species, for example,
the number could go to several hundred millions.
Viruses are classified by International Committee of Taxonomy of Viruses,
or ICTV, into seven orders, 103 families, 22 sub-families
455 general, and 2,827 species
with many thousands
of types unclassified.
classification is generally
used with the new
by David Baltimore, which
is based on the mechanism
of messenger RNA production.
As you know, viruses must
generate messenger RNA to produce
proteins and replicate themselves.
But different mechanisms are used to
achieve this in each virus family.
Viral genome may be double stranded
or single stranded, RNA or DNA,
and may or may not use
reverse transcriptase, or RT.
In addition, single
stranded RNA viruses
may be either positive-sense
or negative, or anti-sense.
This classification places
viruses into seven groups.