Chemistry: molecular biology and microbiology – Vector – per se
Reexamination Certificate
2001-06-26
2003-10-21
Park, Hankyel T. (Department: 1648)
Chemistry: molecular biology and microbiology
Vector, per se
C435S235100, C435S252300, C435S005000, C435S069100, C536S023720, C424S230100
Reexamination Certificate
active
06635477
ABSTRACT:
TECHNICAL FIELD
This invention pertains to the field of virology, specifically to the diagnosis, treatment and prevention of viral infections in humans. More specifically, this invention relates to the diagnosis, treatment and prevention of human cytomegalovirus infections.
BACKGROUND
Human cytomegalovirus (HCMV) is a ubiquitous agent in human populations. Infections are generally asymptomatic, but there can be serious medical sequelae in immunocompromised individuals and in congenitally infected newborns. In immunocompromised individuals, HCMV infection can result in interstitial pneumonia, retinitis progressing to blindness and disseminated infection. Infections in newborns can be severely damaging, with multiple organ involvement including the central nervous system and may also result in auditory damage. The mechanisms of pathogenesis are not understood, although it is believed that host factors, such as cellular and/or humoral immune responses might be involved. See, Alford and Britt, “The Human Herpesviruses”, eds Roizman, B., R. J. Whitley and C. Lopez, Raven Press, New York, 1993, pp 227-55. It has also been speculated that genetic variability (either structural or antigenic or both) among different strains of HCMV could be responsible for the variance in clinical manifestations observed. Pritchett,
J. Virol
. 36:152-61(1980); Lehner,
J. Clin. Microbiol
. 29:2494-2502(1991); Fries,
J. Infect. Dis
. 169:769-74(1994).
Considerable attention has been focused recently on the analysis of strain variation among HCMV isolates. Some twenty different HCMV strains have been isolated and differentiated by restriction analysis of PCR amplified DNA fragments. Chou,
J. Infect. Dis
. 162:738-42(1990).
One strain, the Towne strain, has been developed into a live, attenuated vaccine and administered with some success in renal transplant patients. See Quinnan,
Annals of Int. Med
. 101:478-83(1984); Plotkin,
Lancet
1:528-30(1984). However, Towne strain vaccines who were directly challenged by low-passaged Toledo strain wild-type virus in one study were found to resist challenge doses of only 10 plaque-forming units (pfu) or less. Plotkin,
J. Infect. Dis
. 159:860-65(1989). Therefore, it appears the Towne strain may be overly attenuated, i.e., genetically modified so extensively resulting from serial passage in cell culture that it has lost significant immunogenicity presumably due to the loss of genetic information during the cell passage. Advantageously however, the Towne strain has never been shown to reactivate.
DNA sequence heterogeneity between the Towne strain and another strain of HCMV, AD169, has been found. Pritchett,
J. Virol
. 36:152-61(1980). (A restriction map of the AD169 HCMV genome is disclosed in U.S. Pat. No. 4,762,780.) Variation in the DNA content among other isolated strains of HCMV has also been detected. Huang,
Yale J. Biol. and Med
. 49:29-43(1976). Cleavage patterns of restriction enzyme digests of HCMV DNA of various strains has been analyzed. Kilpatrick,
J. Virol
. 18:1095-1105(1976); LaFemina, “Structural Organization of the DNA Molecules from Human Cytomegalovirus” in
Animal Virus Genetics
, eds. Field, BN and R. Jaenish, Academic Press, NY (1980); Chandler,
J. Gen. Virol
. 67:2179-92(1986); Zaia,
J. Clin. Microbiol
. 28:2602-07(1990). However, although the gross structural organization of the HCMV genome has been determined and strain-to-strain restriction site polymorphism mapped for many of the strains, strain-to-strain differences in the DNA sequences of the HCMV genome have not been determined. Only partial sequences have been deduced and compared, For example, the DNA and amino acid sequences of the envelope glycoprotein B [gpUL55(gB)] of both Towne and AD169 strains have been deduced, see Spaete,
Virology
167:207-25(1988), and compared with various clinical isolates, see Chou,
J. Infect. Dis
. 163:1229-34(1991), to identify conserved regions and regions of variability. In addition, DNA sequence analysis of certain regions of the gp58/116 gene [gpUL55(gB)], the IMP gene and the IE-1/2 enhancer/promoter has been accomplished. Lehner,
J. Clin. Microbiol
. 29:2494-2502(1991).
Whereas the complete DNA sequence of the AD169 strain of HCMV has been deduced, (EMBL Accession No. X17403), the complete DNA sequence of the Towne strain has not to our knowledge been deduced. However, it has been speculated that AD169 and another laboratory strain, Davis, are missing two to four kilobase pairs (kb) of DNA sequence compared to the Towne strain at the extreme internal portions of both L repeats. LeFemina, supra, at 52-53.
The public health impact of HCMV infections has not been well controlled by current treatment strategies or available antiviral chemotherapies. Preventative vaccine strategies are, likely to prove efficacious because of the observations that seropositive renal allograft recipients are protected from severe HCMV disease and maternal immunity protects the fetus from disease after intrauterine infection. Marshall and Plotkin, “Cytomegalovirus Vaccines” in The Human Herpesviruses, eds Roizman, B., R. J. Whitley and C. Lopez, Raven Press, New York, 1993, pps 381-95. However, an additional obstacle to the development of a vaccine for HCMV is the lack of an animal model system that can be used to test the safety and efficacy of vaccine candidates.
There remains a need in the art for efficacious vaccines for the prophylactic treatment of HCMV in humans.
SUMMARY OF THE INVENTION
In one aspect, the invention provides novel HCMV DNA sequences not heretofore recognized or known in the art. These novel HCMV sequences were isolated from the Toledo and Towne strains of HCMV and comprise DNA that is not shared by reference strain AD169 of HCMV. Accordingly, in this aspect the invention provides novel, isolated, Toledo strain HCMV DNA sequences. As used herein, “isolated” means substantially free from other viral DNA sequences with which the subject DNA is typically found in its native, i.e., endogenous, state. These novel Toledo HCMV DNA sequences are characterized by comprising the same or substantially the same nucleotide sequence as in
FIG. 1
(SEQ ID NO:6), or active fragments thereof. The DNA sequences may include 5′ and 3′ non-coding sequences flanking the coding sequence. The DNA sequences may be in inverted orientation with respect to the orientation shown in FIG.
1
. Segments or fragments of the DNA sequence shown in
FIG. 1
(SEQ ID NO:6) may be rearranged or inverted internally. The DNA sequences of the invention also comprise nucleotide sequences capable of hybridizing under stringent conditions, or which would be capable of hybridizing under said conditions but for the degeneracy of the genetic code to a sequence corresponding to the sequence of FIG.
1
.
FIG. 1
(SEQ ID NO:6) illustrates the DNA sequence of the novel Toledo strain HCMV. Twenty one open reading frames (ORFs) were identified in this sequence. The putative amino acid sequences of these novel Toledo strain HCMV ORFs are enumerated in sequence identification numbers 7 through 27, pages 58 through 78, infra. In
FIG. 1
, the beginning and ending of the 21 ORFs are identified by the arrows and the designations “UL133”, “UL134”, etc. (see infra.). In rearranged sequences of the invention, novel open reading frames may be created or destroyed.
In another aspect, the invention provides additional novel HCMV DNA sequences not heretofore recognized or known in the art. These additional sequences were isolated from the Towne strain of HCMV and comprise DNA that is not shared by the AD 169 strain or by the Toledo strain of HCMV. Accordingly, in this aspect the invention provides novel Towne strain HCMV sequences. These novel Towne HCMV DNA sequences are characterized by as comprising the same or substantially the same nucleotide sequence as in
FIG. 2
(SEQ ID NO:1), or active fragments thereof. The DNA sequence may include 5′ and 3′ non-coding sequences flanking the coding sequence. The DNA sequences of the invention also comprise nu
Cha Tai-An
Spaete Richard
Evans Jonathan Klein
Med Immune Vaccines, Inc.
Park Hankyel T.
Quine Intellectual Property Law Group P.C.
LandOfFree
Human cytomegalovirus DNA sequences does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Human cytomegalovirus DNA sequences, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Human cytomegalovirus DNA sequences will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3143349