Organic compounds -- part of the class 532-570 series – Organic compounds – Carbohydrates or derivatives
Reexamination Certificate
1994-03-14
2001-12-25
Chin, Christopher L. (Department: 1641)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carbohydrates or derivatives
C424S191100, C424S268100, C424S272100, C435S069300, C435S069700, C435S070100, C435S071100, C435S320100, C435S455000, C435S471000, C435S325000, C435S243000, C514S04400A, C536S023500
Reexamination Certificate
active
06333406
ABSTRACT:
BACKGROUND
Malaria is a significant global health problem. It is widespread, and constitutes a growing health problem of major proportions, particularly in developing countries.
Malaria is caused by several species of the genus
Plasmodium
, the most virulent species being
Plasmodium falciparum
(
P. falciparum
). Parasites growing in erythrocytes are responsible for the pathological manifestations of the disease in man. During the blood stage of infection,
P. falciparum
parasites infect the cells and develop within the erythrocytes through three successive, morphologically distinct stages known as ring, trophozoites and schizonts. A mature schizont eventually produces multiple infectious particles, known as merozoites, which are released upon rupture of the red blood cells. The merozoites invade new red blood cells after a short extracellular life in the blood.
The increased resistance of the malaria parasite to drugs, as well as the resistance of the mosquito vector to insecticide, has increased the need for a malaria vaccine. H. S. Banyal and J. Inselburg,
Am. J. Trop. Med. Hyg
., 34(6): 1055-1064 (1985). One approach to the development of a vaccine has been to use monoclonal antibodies to identify and characterize specific malarial antigens involved in antibody-sensitive processes that are essential to the maintenance of the parasite growth cycle. These antibodies are known as “parasite inhibitory” antibodies. These parasite inhibitory antibodies can be induced by a host's immune response to the complementary antigens. Such an antigen, or combination of antigens, could therefore provide the basis for an effective malarial vaccine. Some parasite inhibitory antibodies have been isolated and the
P. falciparum
parasite antigens they recognize have been identified by H. S. Banyal and J. Inselburg, in
Am. J. Trop. Med. Hyg
., 34(6):1055-1064 (1985). See also, P. Deplace, et al.,
Molecular and Biochemical Parasitology
, 23: 193-201 (1987); J. L. Weber, et al.,
Molecular Strategies of Parasitic Invasion
, Agubian, Goodman and Nogueira (Eds.), Alan R. Liss, Inc., New York, N.Y. pp. 379-388 (1987); P. Deplace, et al.,
Molecular and Biochemical Parasitology
, 17: 339-251 (1985); J. D. Chulay, et al.,
The Journal of Immunology
, 139: 2768-2774 (1987); and A. Bhatia, et al.,
Am. J. Trop. Med
., 36(1): 15-19(1987).
The key to developing an antimalarial vaccine based on a defined antigen is to isolate and characterize the gene encoding the antigen recognized by a parasite inhibitory antibody so it may be manipulated by gene cloning techniques to provide sufficient amounts of appropriate antigen for vaccine production.
Available approaches to diagnosing, preventing and treating malaria are limited in their effectiveness and must be improved if a solution is to be found for the important public health problem malaria represents worldwide.
SUMMARY OF THE INVENTION
The invention pertains to an isolated nucleic acid sequence which encodes the SERA protein antigen of the malaria parasite
Plasmodium falciparum
(
P. falciparum
), which antigen is capable of eliciting parasite inhibitory antibodies in a parasite host. The term “SERA” is derived from serine repeat antigen based on the presence of a serine repeat sequence in the amino acid sequence of the protein.
In particular, the invention comprises the
P. falciparum
cDNA having the nucleotide sequence shown in
FIG. 2
(SEQ ID NO: 1), the amino acid sequence derived from it shown in
FIG. 3
(SEQ ID NO: 2), and the genomic DNA sequence shown in
FIG. 6
(SEQ ID NO: 3). The isolated genomic DNA sequence of the invention can include the SERA gene regulatory sequences contained in the 5′ flanking sequence of the gene, and the signal sequences, also shown in FIG.
3
and
FIG. 6
(SEQ ID NO: 2 and 3, respectively). The regulatory sequence can be used to direct expression of the SERA gene, or they may be used independent of the SERA DNA sequences, to direct the expression of other DNA sequences, especially other malarial DNA sequences. The signal sequences can be used to direct exportation of the SERA protein, or independent of the SERA DNA, to direct exportation of a protein by a cell.
The invention also pertains to the immunogenic protein antigen, SERA, or immunogenic equivalents thereof, encoded by the isolated DNA of the invention. The amino acid sequence of the protein antigen is shown in FIG.
3
and
FIG. 6
(SEQ ID NO: 2 and 3, respectively). The protein can be produced by recombinant DNA techniques. For example, cDNA of the invention can be incorporated into an expression vector and the vector used to infect a host cell for expression of the SERA antigen.
The invention further pertains to a method of producing a malarial protein, in
E. coli
cells, which elicits a malarial inhibitory antibody. This method includes: transforming an
E. coli
cell with an expression vector containing DNA encoding a malarial protein which protein is reactive with antibody inhibitory of
Plasmodium falciparum
wherein the DNA encoding a malarial protein comprises the
E. coli
codons comparable to
P. falciparum
codons based on usage preference for the amino acids of the malarial protein; then culturing the cell to produce the protein as the major
E. coli
protein that is synthesized; and then recovering the protein from the cell in a pure form to facilitate the commercial preparation of the protein. The method can be used, for example, with the nucleotide sequences shown in
FIGS. 11
,
12
and/or
21
(SEQ ID NO: 14, 16 and 18, respectively). The invention also pertains to the nucleotide sequences shown in
FIGS. 11
,
12
and
21
(SEQ ID NO: 14, 16 and 18, respectively) and the amino acid sequences for which they code (SEQ ID NO: 15, 17, and 19, respectively). The polypeptides are designated as SE47 (
FIG. 21
, SEQ ID NO: 19), SE47′ (
FIG. 11
, SEQ ID NO: 15) and SE50A (
FIG. 12
, SEQ ID NO: 17). Further, isolated polypeptides produced in
E. coli
are included in the invention.
This invention includes a malaria vaccine which is composed of the SERA antigen or a portion thereof, in a pharmaceutically acceptable carrier, and a method of vaccinating against malaria with this vaccine. Also included in the invention are malaria vaccines which include a malarial protein produced in
E. coli
cells in combination with a pharmaceutically acceptable carrier. In addition, vaccines which include DNA which encode all or a portion of the SERA protein in a pharmaceutically acceptable carrier are included in the invention.
REFERENCES:
patent: 4735799 (1988-04-01), Patarroyo
patent: 4767622 (1988-08-01), Ristic et al.
patent: 4906564 (1990-03-01), Lyon et al.
patent: 4978621 (1990-12-01), Ardeshir et al.
patent: 5028425 (1991-07-01), Good et al.
patent: 5194587 (1993-03-01), Knapp et al.
patent: 0 154 454 (1985-09-01), None
patent: 0 283 882 (1988-09-01), None
patent: WO 87/00533 (1987-01-01), None
patent: WO 87/03882 (1987-07-01), None
Knapp et al., “Molecular Cloning, genomic structures and localization in a blood stage antigen ofPlasmodium falciparumcharacterized by a serine stretch,”Molecular and Biochemical Parasitology, 32(1989) 73-84.*
Maniatis et al.,Molecular Cloning: A Laboratory Manual(Cold Spring Harbor Laboratory 1982); Chapter 10, pp. 310-361.*
Banyal, H.S. and J. Inselburg, “Isolation and Characterization of Parasite-InhibitoryPlasmodium falciparumMonoclonal Antibodies”Am J. Trop. Med. Hyg., vol. 34, No. 6, pp. 1055-1064, 1985.
Bhatia, A. et al., “Immunochemical Analysis of a Major Antigen ofPlasmodium falciparum(p126) Among Ten Geographic Isolates”Am. J. Trop. Med. Hyg., vol. 36, No. 1, pp. 15-19, 1987.
Chulay, J.D. et al., “Monoclonal Antibody Characterization ofPlasmodium falciparumAntigens in Immune Complexes Formed When Schizonts Rupture in the Presence of Immune Serum”J. Immunology, vol. 139, pp. 2768-2774, 1987.
Delplace, P. et al., “Localization, biosynthesis, processing and isolation of a major 126 kDa antigen of the parasitophorous vacuole ofPlasmodium falciparum”Molecular and Biochemical Parasitology, vol. 2
Bzik David J.
Horii Toshihiro
Inselburg Joseph W.
Sugiyama Tomohiko
Chin Christopher L.
DeConti, Jr, Esq. Giulio A.
Grun James L.
Lahive & Cockfield LLP
Williams, Esq. Megan E.
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