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Biomedical subjects

Sanjai Kumar

Publications and source records attributed to Sanjai Kumar.

At least 19 recordsLinked to original sources
PubMed2006

A novel chimeric Plasmodium vivax circumsporozoite protein induces biologically functional antibodies that recognize both VK210 and VK247 sporozoites.

A successful vaccine against Plasmodium vivax malaria would significantly improve the health and quality of the lives of more than 1 billion people around the world. A subunit vaccine is the only option in the absence of long-term culture of P. vivax parasites. The circumsporozoite protein that covers the surface of Plasmodium sporozoites is one of the best-studied malarial antigens and the most promising vaccine in clinical trials. We report here the development of a novel "immunologically optimal" recombinant vaccine expressed in Escherichia coli that encodes a chimeric CS protein encompassing repeats from the two major alleles, VK210 and VK247. This molecule is widely recognized by sera from patients naturally exposed to P. vivax infection and induces a highly potent immune response in genetically disparate strains of mice. Antibodies from immunized animals recognize both VK210 and VK247 sporozoites. Furthermore, these antibodies appear to be protective in nature since they cause the agglutination of live sporozoites, an in vitro surrogate of sporozoite infectivity. These results strongly suggest that recombinant CS is biologically active and highly immunogenic across major histocompatibility complex strains and raises the prospect that in humans this vaccine may induce protective immune responses.

Animals↗
PubMed2006

Global analysis of protein tyrosine phosphatase activity with ultra-sensitive fluorescent probes.

Protein tyrosine phosphatases (PTPs) consist of a large family of enzymes known to play important roles in controlling virtually all aspects of cellular processes. However, assigning functional significance of PTPs in normal physiology and in diseases remains a major challenge in cell signaling. Since the function of a PTP is directly associated with its intrinsic activity, which is subject to post-translational regulation, new tools are needed to monitor the dynamic activities of PTPs, rather than mere abundance, on a global scale within the physiologically relevant environment of cells. To meet this objective, we report the synthesis and characterization of two rhodamine-conjugated probes that covalently label the active site of the PTPs in an activity-dependent manner, thus providing a direct readout of PTP activity and superior sensitivity, robustness, and quantifiability to previously reported biotinylated probes. We present evidence that the fluorescent probes can be used to identify new PTP markers and targets for potential diagnosis and treatment of human diseases. We also show that the fluorescent probes are capable of monitoring H(2)O(2)-mediated PTP inactivation, which should facilitate the study of regulated H(2)O(2) production as a new tier of control over tyrosine phosphorylation-dependent signal transduction. The ability to profile the entire PTP family on the basis of changes in their activity is expected to yield new functional insights into pathways regulated by PTPs and contribute to the discovery of PTPs as novel therapeutic targets.

Biotin↗
PubMed2005

An immunologically cryptic epitope of Plasmodium falciparum circumsporozoite protein facilitates liver cell recognition and induces protective antibodies that block liver cell invasion.

Circumsporozoite, a predominant surface protein, is involved in invasion of liver cells by Plasmodium sporozoites, which leads to malaria. We have previously reported that the amino terminus region (amino acids 27-117) of P. falciparum circumsporozoite protein plays a critical role in the invasion of liver cells by the parasite. Here we show that invasion-blocking antibodies are induced by a polypeptide encoding these 91 amino acids, only when it is presented in the absence of the rest of the protein. This suggests that when present in the whole protein, the amino terminus remains immunologically cryptic. A single reactive epitope was identified and mapped to a stretch of 21 amino acids from position 93 to 113. The epitope is configurational in nature, since its recognition was affected by deleting as little as 3 amino acids from either end of the 21-residue peptide. Lysine 104, the only known polymorphic position in the epitope, affected its recognition by the antibodies, and its conversion to leucine in the protein led to a substantial loss of binding activity of the protein to the hepatocytes. This indicated that in the protein, the epitope serves as a binding ligand and facilitates the interaction between sporozoite and hepatic cells. When considered along with the observation that in its native state this motif is immunologically unresponsive, we suggest that hiding functional moieties of the protein from the immune system is an evasion strategy to preserve liver cell binding function and may be of importance in designing anti-sporozoite vaccines.

Amino Acid Sequence↗
PubMed2005

Small molecule approach to studying protein tyrosine phosphatase.

Understanding the function of protein tyrosine phosphatases (PTPs) is crucial to deciphering cellular signaling in higher organisms. Of the 100 putative PTPs in human genome, only a little is known about their precise biological functions. Thus establishing novel ways to study PTP function remains a top priority among researchers. Classical genetics and more recently the use of RNA interference (RNAi) for gene silencing remains a popular choice to study function. However, the one gene-one function hypothesis is now recognized as an oversimplified scenario, especially among the signaling proteins such as PTPs. Therefore, there is a need to understand gene function in an appropriate cellular context. Since proteins are the work horses of the cell, alteration of protein function by various means is a particularly attractive strategy. In this context, the chemical approach, where a small molecule is used to affect the function of the desired protein is increasingly being recognized as a method of choice. In this review, we describe how small molecules can be used to study the function of a prototypical PTP, PTP1B, which is a negative regulator in insulin signaling. This includes our initial strategies for finding the most potent and specific PTP1B inhibitor to date, synthesizing cell permeable analogues suitable for cellular studies, and using them to dissect the role of PTP1B in the insulin signaling pathway. This approach is potentially general and thus could be utilized to study the function of other PTPs.

Biological Assay↗
PubMed2005

Identification, cloning, expression, and characterization of the gene for Plasmodium knowlesi surface protein containing an altered thrombospondin repeat domain.

Proteins present on the surface of malaria parasites that participate in the process of invasion and adhesion to host cells are considered attractive vaccine targets. Aided by the availability of the partially completed genome sequence of the simian malaria parasite Plasmodium knowlesi, we have identified a 786-bp DNA sequence that encodes a 262-amino-acid-long protein, containing an altered version of the thrombospondin type I repeat domain (SPATR). Thrombospondin type 1 repeat domains participate in biologically diverse functions, such as cell attachment, mobility, proliferation, and extracellular protease activities. The SPATR from P. knowlesi (PkSPATR) shares 61% and 58% sequence identity with its Plasmodium falciparum and Plasmodium yoelii orthologs, respectively. By immunofluorescence analysis, we determined that PkSPATR is a multistage antigen that is expressed on the surface of P. knowlesi sporozoite and erythrocytic stage parasites. Recombinant PkSPATR produced in Escherichia coli binds to a human hepatoma cell line, HepG2, suggesting that PkSPATR is a parasite ligand that could be involved in sporozoite invasion of liver cells. Furthermore, recombinant PkSPATR reacted with pooled sera from P. knowlesi-infected rhesus monkeys, indicating that native PkSPATR is immunogenic during infection. Further efficacy evaluation studies in the P. knowlesi-rhesus monkey sporozoite challenge model will help to decide whether the SPATR molecule should be developed as a vaccine against human malarias.

Amino Acid Sequence↗
PubMed2005

Genome-wide expression profiling in malaria infection reveals transcriptional changes associated with lethal and nonlethal outcomes.

High-density oligonucleotide microarrays are widely used to study gene expression in cells exposed to a variety of pathogens. This study addressed the global genome-wide transcriptional activation of genes in hosts infected in vivo, which result in radically different clinical outcomes. We present an analysis of the gene expression profiles that identified a set of host biomarkers which distinguish between lethal and nonlethal blood stage Plasmodium yoelii malaria infections. Multiple biological replicates sampled during the course of infection were used to establish statistically valid sets of differentially expressed genes. These genes that correlated with the intensity of infection were used to identify pathways of cellular processes related to metabolic perturbations, erythropoiesis, and B-cell immune responses and other innate and cellular immune responses. The transcriptional apparatus that controls gene expression in erythropoiesis was also differentially expressed and regulated the expression of target genes involved in the host's response to malaria anemia. The biological systems approach provides unprecedented opportunities to explore the pathophysiology of host-pathogen interactions in experimental malaria infection and to decipher functionally complex networks of gene and protein interactions.

Animals↗
PubMed2005

Antimalarial drugs: current status and new developments.

Malaria continues to be a major threat in the developing world, with > 1 million clinical episodes and 3000 deaths every day. In the last century, malaria claimed between 150 and 300 million lives, accounting for 2 - 5% of all deaths. Currently approximately 40% of the world population resides in areas of active malaria transmission. The disease symptoms are most severe in young children and pregnant women. A total of 90% of the disease-associated mortality occurs in Subsaharan Africa, despite the fact that malaria is indigenous to most tropical regions. A licensed vaccine for malaria has not become a reality and antimalarial drugs are the only available method of treatment. Although chloroquine, the first synthetically developed antimalarial, proved to be an almost magical cure for > 30 years, the emergence and spread of chloroquine-resistant parasites has made it virtually ineffective in most parts of the world. Currently, artemisinin, a plant-derived antimalarial, is the only available drug that is globally effective against the parasite. Although several new drugs have been introduced in the past 30 years, widespread or isolated cases of resistance indicate that their window of effectiveness will be limited. Thus, there is an urgent need to develop new therapeutics and regimens for malaria control. This article presents an overview of the currently available antimalarial chemotherapy options and the efforts being undertaken to develop new drugs based on both the recent technological advances and modifications to the old remedies, and on combination therapies.

Animals↗
PubMed2004

Activity-based probes for protein tyrosine phosphatases.

Protein tyrosine phosphatases (PTPs) are involved in the regulation of many aspects of cellular activity including proliferation, differentiation, metabolism, migration, and survival. Given the large number and complexity of PTPs in cell signaling, new strategies are needed for the integrated analysis of PTPs in the whole proteome. Unfortunately, the activities of many PTPs are tightly regulated by posttranslational mechanisms, limiting the utility of standard genomics and proteomics methods for functional characterization of these enzymes. To facilitate the global analysis of PTPs, we designed and synthesized two activity-based probes that consist of alpha-bromobenzylphosphonate as a PTP-specific trapping device and a linker that connects the trapping device with a biotin tag for visualization and purification. We showed that these probes are active site-directed irreversible inactivators of PTPs and form a covalent adduct with PTPs involving the active site Cys residue. Additionally, we demonstrated that the probes are extremely specific toward PTPs while remaining inert to other proteins, including the whole proteome from Escherichia coli. Consequently, these activity-based PTP probes can be used to profile PTP activity in complex proteomes. The ability to interrogate the entire PTP family on the basis of changes in their activity should greatly accelerate both the assignment of PTP function and the identification of potential therapeutic targets.

Binding Sites↗
PubMed2004

Kinetics of turnover of cefotaxime by the Enterobacter cloacae P99 and GCl beta-lactamases: two free enzyme forms of the P99 beta-lactamase detected by a combination of pre- and post-steady state kinetics.

Third-generation cephalosporins bearing oximino side chains are resistant to hydrolysis by class C beta-lactamases such as that from Enterobacter cloacae P99. For example, steady state parameters for hydrolysis of cefotaxime by this enzyme are as follows: k(cat) = 0.41 s(-1), K(m) = 17.2 microM, and k(cat)/K(m) = 2.3 x 10(4) s(-1) M(-1). On the other hand, however, the K(i) value for cefotaxime as an inhibitor of cephalothin hydrolysis is 27 nM. The discrepancy between K(m) and K(i) indicated that a real steady state had not been achieved in at least one of these experiments. Analysis indicated that only two to three cefotaxime turnovers occurred during the K(i) determination. This suggested that the first few turnovers of cefotaxime by the P99 beta-lactamase may be different from those in the subsequent steady state. A direct pre-steady state experiment confirmed this hypothesis. The simplest reaction scheme that fitted the data involved replacement of the initial enzyme form, E, which bound cefotaxime tightly, with a second more weakly binding form, E', by partitioning of the acyl-enzyme intermediate during the first few turnovers. Steady state turnover of cefotaxime then largely involved E' as the free enzyme form. E' slowly reverted to E in the post-steady state regime. Further evidence for this scheme included quantitative analysis of the post-steady state and observation of a difference in the catalytic activity of E and E' in 2 M ammonium sulfate. The kinetics of P99 beta-lactamase-catalyzed hydrolysis of an acyclic depsipeptide substrate bearing a third-generation cephalosporin side chain showed that the side chain is necessary but not sufficient for production of resistance to beta-lactamase; a combination of the side chain and the dihydrothiazine ring of a cephalosporin is required. The beta-lactamase of E. cloacae GC1, an extended spectrum mutant of the P99 enzyme, rapidly hydrolyzes third-generation cephalosporins, without the structural transition described above. The flexibility of the extended Omega loop of the GC1 enzyme probably leads to this situation. Conformational restriction of the loop in the P99 enzyme is probably responsible for the long-lived acyl-enzyme intermediate and the transition to E' induced by cefotaxime.

Acylation↗
PubMed2004

CpG oligodeoxynucleotide and Montanide ISA 51 adjuvant combination enhanced the protective efficacy of a subunit malaria vaccine.

Unmethylated CpG dinucleotide motifs present in bacterial genomes or synthetic oligodeoxynucleotides (ODNs) serve as strong immunostimulatory agents in mice, monkeys and humans. We determined the adjuvant effect of murine CpG ODN 1826 on the immunogenicity and protective efficacy of the Saccharomyces cerevisiae-expressed 19-kDa C-terminal region of merozoite surface protein 1 (yMSP1(19)) of the murine malaria parasite Plasmodium yoelii. We found that in C57BL/6 mice, following sporozoite challenge, the degree of protective immunity against malaria induced by yMSP1(19) in a formulation of Montanide ISA 51 (ISA) plus CpG ODN 1826 was similar or superior to that conferred by yMSP1(19) emulsified in complete Freund's adjuvant (CFA/incomplete Freund's adjuvant). In total, among mice immunized with yMSP1(19), 22 of 32 (68.7%) with ISA plus CpG 1826, 0 of 4 (0%) with CFA/incomplete Freund's adjuvant, 0 of 4 (0%) with CpG 1826 mixed with ISA (no yMSP1(19)), and 0 of 11 (0%) with CpG 1826 alone were completely protected against development of erythrocytic stage infection after sporozoite challenge. The adjuvant effect of CpG ODN 1826 was manifested as both significantly improved complete protection from malaria (defined as the absence of detectable erythrocytic form parasites) (P = 0.007, chi square) and reduced parasite burden in infected mice. In vivo depletions of interleukin-12 and gamma interferon cytokines and CD4+ and CD8+ T cells in vaccinated mice had no significant effect on immunity. On the other hand, immunoglobulin G (IgG) isotype levels appeared to correlate with protection. Inclusion of CpG ODN 1826 in the yMSP1(19) plus ISA vaccine contributed towards the induction of higher levels of IgG2a and IgG2b (Th1 type) antibodies, suggesting that CpG ODN 1826 caused a shift towards a Th1 type of immune response that could be responsible for the higher degree of protective immunity. Our results indicate that this potent adjuvant formulation should be further evaluated for use in clinical trials of recombinant malarial vaccine candidates.

Adjuvants, Immunologic↗
PubMed2004

Measuring the effects of an ever-changing environment on malaria control.

The effectiveness of malaria control measures depends not only on the potency of the control measures themselves but also upon the influence of variables associated with the environment. Environmental variables have the capacity either to enhance or to impair the desired outcome. An optimal outcome in the field, which is ultimately the real goal of vaccine research, will result from prior knowledge of both the potency of the control measures and the role of environmental variables. Here we describe both the potential effectiveness of control measures and the problems associated with testing in an area of endemicity. We placed canaries with different immunologic backgrounds (e.g., naïve to malaria infection, vaccinated naïve, and immune) directly into an area where avian malaria, Plasmodium relictum, is endemic. In our study setting, canaries that are naïve to malaria infection routinely suffer approximately 50% mortality during their first period of exposure to the disease. In comparison, birds vaccinated and boosted with a DNA vaccine plasmid encoding the circumsporozoite protein of P. relictum exhibited a moderate degree of protection against natural infection (P < 0.01). In the second year we followed the fate of all surviving birds with no further manipulation. The vaccinated birds from the first year were no longer statistically distinguishable for protection against malaria from cages of naïve birds. During this period, 36% of vaccinated birds died of malaria. We postulate that the vaccine-induced protective immune responses prevented the acquisition of natural immunity similar to that concurrently acquired by birds in a neighboring cage. These results indicate that dominant environmental parameters associated with malaria deaths can be addressed before their application to a less malleable human system.

Animals↗
PubMed2003

Hydrolysis of third-generation cephalosporins by class C beta-lactamases. Structures of a transition state analog of cefotoxamine in wild-type and extended spectrum enzymes.

Bacterial resistance to the third-generation cephalosporins is an issue of great concern in current antibiotic therapeutics. An important source of this resistance is from production of extended-spectrum (ES) beta-lactamases by bacteria. The Enterobacter cloacae GC1 enzyme is an example of a class C ES beta-lactamase. Unlike wild-type (WT) forms, such as the E. cloacae P99 and Citrobacter freundii enzymes, the ES GC1 beta-lactamase is able to rapidly hydrolyze third-generation cephalosporins such as cefotaxime and ceftazidime. To understand the basis for this ES activity, m-nitrophenyl 2-(2-aminothiazol-4-yl)-2-[(Z)-methoxyimino]acetylaminomethyl phosphonate has been synthesized and characterized. This phosphonate was designed to generate a transition state analog for turnover of cefotaxime. The crystal structures of complexes of the phosphonate with both ES GC1 and WT C. freundii GN346 beta-lactamases have been determined to high resolution (1.4-1.5 Angstroms). The serine-bound analog of the tetrahedral transition state for deacylation exhibits a very different binding geometry in each enzyme. In the WT beta-lactamase the cefotaxime-like side chain is crowded against the Omega loop and must protrude from the binding site with its methyloxime branch exposed. In the ES enzyme, a mutated Omega loop adopts an alternate conformation allowing the side chain to be much more buried. During the binding and turnover of the cefotaxime substrate by this ES enzyme, it is proposed that ligand-protein contacts and intra-ligand contacts are considerably relieved relative to WT, facilitating positioning and activation of the hydrolytic water molecule. The ES beta-lactamase is thus able to efficiently inactivate third-generation cephalosporins.

Amino Acid Sequence↗
PubMed2003

Molecular mechanism of host specificity in Plasmodium falciparum infection: role of circumsporozoite protein.

Plasmodium falciparum sporozoites invade liver cells in humans and set the stage for malaria infection. Circumsporozoite protein (CSP), a predominant surface antigen on sporozoite surface, has been associated with the binding and invasion of liver cells by the sporozoites. Although CSP across the Plasmodium genus has homology and conserved structural organization, infection of a non-natural host by a species is rare. We investigated the role of CSP in providing the host specificity in P. falciparum infection. CSP from P. falciparum, P. gallinaceum, P. knowlesi, and P. yoelii species representing human, avian, simian, and rodent malaria species were recombinantly expressed, and the proteins were purified to homogeneity. The recombinant proteins were evaluated for their capacity to bind to human liver cell line HepG2 and to prevent P. falciparum sporozoites from invading these cells. The proteins showed significant differences in the binding and sporozoite invasion inhibition activity. Differences among proteins directly correlate with changes in the binding affinity to the sporozoite receptor on liver cells. P. knowlesi CSP (PkCSP) and P. yoelii CSP (PyCSP) had 4,790- and 17,800-fold lower affinity for heparin in comparison to P. falciparum CSP (PfCSP). We suggest that a difference in the binding affinity for the liver cell receptor is a mechanism involved in maintaining the host specificity by the malaria parasite.

Animals↗
PubMed2003

PfSPATR, a Plasmodium falciparum protein containing an altered thrombospondin type I repeat domain is expressed at several stages of the parasite life cycle and is the target of inhibitory antibodies.

The annotated sequence of chromosome 2 of Plasmodium falciparum was examined for genes encoding proteins that may be of interest for vaccine development. We describe here the characterization of a protein with an altered thrombospondin Type I repeat domain (PfSPATR) that is expressed in the sporozoite, asexual, and sexual erythrocytic stages of the parasite life cycle. Immunoelectron microscopy indicated that this protein was expressed on the surface of the sporozoites and around the rhoptries in the asexual erythrocytic stage. An Escherichia coli-produced recombinant form of the protein bound to HepG2 cells in a dose-dependent manner and antibodies raised against this protein blocked the invasion of sporozoites into a transformed hepatoma cell line. Sera from Ghanaian adults and from a volunteer who had been immunized with radiation-attenuated P. falciparum sporozoites specifically recognized the expression of this protein on transfected COS-7 cells. These data support the evaluation of this protein as a vaccine candidate.

Amino Acid Sequence↗
PubMed2003

Age-dependent impairment of IgG responses to glycosylphosphatidylinositol with equal exposure to Plasmodium falciparum among Javanese migrants to Papua, Indonesia.

Immune responses directed at glycosylphosphatidylinositol (GPI) anchors of Plasmodium falciparum may offer protection against symptomatic malaria. To independently explore the effect of age on generation of the anti-GPI IgG response, we measured serum anti-GPI IgGs in a longitudinal cohort of migrant Javanese children (6-12 years old) and adults (> or = 20 years old) with equivalent numbers of exposures to P. falciparum in Papua, Indonesia. While the peak response in adults was achieved after a single infection, comparable responses in children required > or = 3-4 infections. Significantly fewer children (16%) than adults (41%) showed a high (optical density > 0.44) anti-GPI IgG response (odds ratio [OR] = 3.8, 95% confidence interval [CI] = 2.3-6.3, P < 0.0001), and adults were more likely to show a persistently high response (OR = 5.5, 95% CI = 1.0-56.8, P = 0.03). However, the minority of children showing a strong response were significantly less likely to experience symptoms with subsequent parasitemia compared with those with a weak response (OR = 4.0, 95% CI = 1.1-13.8, P = 0.02). This effect was not seen among high- and low-responding adults (OR = 1.2, 95% CI = 0.5-2.8, P = 0.60). Host age, independent of cumulative exposure, apparently represents a key determinant of the quantitative and qualitative nature of the IgG response to P. falciparum GPI.

Adult↗
PubMed2002

Safety, tolerability, and lack of antibody responses after administration of a PfCSP DNA malaria vaccine via needle or needle-free jet injection, and comparison of intramuscular and combination intramuscular/intradermal routes.

Introduction of a new vaccine requires choosing a delivery system that provides safe administration and the desired level of immunogenicity. The safety, tolerability, and immunogenicity of three monthly 2.5-mg doses of a PfCSP DNA vaccine were evaluated in healthy volunteers as administered intramuscularly (IM) by needle, IM by jet injection (Biojector or IM/intradermally (ID) by jet injection. Vaccine administration was well-tolerated. Adverse events were primarily mild and limited to the site of injection (98%). Jet injections (either IM or ID) were associated with approximately twice as many adverse events per immunization as needle IM, but nevertheless were strongly and consistently preferred in opinion polls taken during the study. No volunteers had clinically significant biochemical or hematologic changes or detectable anti-dsDNA antibodies. In conclusion, the injection of Plasmodium falciparum circumsporozoite (PfCSP) DNA vaccine appeared to be safe and well-tolerated when administered by any of the three modes of delivery. However, despite improved antibody responses following both jet injection and ID delivery in animal models, no antibodies could be detected in volunteers by immunofluorescence antibody test (IFAT) or enzyme-linked immunosorbent assay (ELISA) after DNA vaccination.

Animals↗
PubMed2002

A DNA vaccine encoding the 42 kDa C-terminus of merozoite surface protein 1 of Plasmodium falciparum induces antibody, interferon-gamma and cytotoxic T cell responses in rhesus monkeys: immuno-stimulatory effects of granulocyte macrophage-colony stimulating factor.

We have constructed a DNA plasmid vaccine encoding the C-terminal 42-kDa region of the merozoite surface protein 1 (pMSP1(42)) from the 3D7 strain of Plasmodium falciparum (Pf3D7). This plasmid expressed recombinant MSP1(42) after in vitro transfection in mouse VM92 cells. Rhesus monkeys immunized with pMSP1(42) produced antibodies reactive with Pf3D7 infected erythrocytes by IFAT, and by ELISA against yeast produced MSP1(19) (yMSP1(19)). Immunization also induced antigen specific T cell responses as measured by interferon-gamma production, and by classical CTL chromium release assays. In addition, immunization with pMSP1(42) primed animals for an enhanced antibody response to a subsequent boost with the recombinant yMSP1(19). We also evaluated Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) as an adjuvant for pMSP1(42.) We tested both rhesus GM-CSF expressed from a DNA plasmid, and E. coli produced recombinant human GM-CSF. Plasmids encoding rhesus GM-CSF (prhGM-CSF) and human GM-CSF (phuGM-CSF) were constructed; these plasmids expressed bio-active recombinant GMCSF. Co-immunization with a mixture of prhGM-CSF and pMSP1(42) induced higher specific antibody responses after the first dose of plasmid, but after three doses of DNA monkeys immunized with or without prhGM-CSF had the same final antibody titers and T cell responses. In comparison, rhuGM-CSF protein did not lead to accelerated antibody production after the first DNA dose. However, antibody titers were maintained at a slightly higher level in monkeys receiving GM-CSF protein, and they had a higher response to boosting with recombinant MSP1(19). The GM-CSF plasmid or protein appears to be less potent as an adjuvant in rhesus monkeys than each is in mice, and more work is needed to determine if GM-CSF can be a useful adjuvant in DNA vaccination of primates.

Adjuvants, Immunologic↗