Retraction Note: α-santalol inhibits the angiogenesis and growth of human prostate tumor growth by targeting vascular endothelial growth factor receptor 2-mediated AKT/mTOR/P70S6K signaling pathway

This article has been retracted. Please see the Retraction Notice for more detail: https://doi.org/10.1186/1476-4598-12-147.

EVALUATION OF INAPPROPRIATE PRESCRIPTIONS IN THE GERIATRIC POPULATION OF AN URBAN SLUM IN BANGALORE

Although the over 60 years age population constitutes approximately 8% of the total population, 30% of total medication is prescribed for this age group. Chronic diseases and polypharmacy in the elderly population increase the risk of inappropriate drug use. Some physicians prescribe medications without reviewing other supplements and medications used by the elder patient. This polypharmacy results in many adverse drug interactions and reactions. The purpose of this study was to identify older patients who were prescribed inappropriate drugs, according to START/STOPP criteria. To estimate the prevalence of inappropriate prescriptions amongst the elderly residing in an urban slum under the field practice area of Urban Health and Training Center (UHTC) of a tertiary medical college; to assess polypharmacy and morbidity pattern in these elderly. A cross-sectional study was conducted among the elderly, aged 65 years and above, residing in an urban slum under the field practice area of a tertiary medical college. A total of 215 elderly were chosen from the study area by simple random sampling. Data regarding socio-demographic profile and medication usage was collected using a pre-tested semistructured questionnaire through individual interview. START/STOPP criteria were used to identify potentially inappropriate prescriptions. The prevalence of PIPs was 43.3% and of PIOs was 20.9%. Polypharmacy was found in 36.7% of elderly population. Mean number of medications used by the study population was 6.19±2.43 (range was 1-10). The most common morbidity present in the study population was Arthritis in 34.9% followed by hypertension in 13% (28) of elderly. The faulty prescription commissions and omissions have created a significant issue of polypharmacy. This study only provides a baseline data about inappropriate prescriptions and polypharmacy. A multi-pronged approach, involving healthcare workers and policy makers is required to address this issue to optimize the elderly pharmacotherapy and thus health care.

Short and dysfunctional telomeres sensitize the kidneys to develop fibrosis

Accumulation of short telomeres is a hallmark of aging. Mutations in telomerase or telomere-binding proteins lead to telomere shortening or dysfunction and are at the origin of human pathologies known as 'telomere syndromes', which are characterized by loss of the regenerative capacity of tissues and fibrotic pathologies. Here, we generated two mouse models of kidney fibrosis, either by combining telomerase deficiency to induce telomere shortening and a low dose of folic acid, or by conditionally deleting Trf1, a component of the shelterin telomere protective complex, from the kidneys. We find that short telomeres sensitize the kidneys to develop fibrosis in response to folic acid and exacerbate the epithelial-to-mesenchymal transition (EMT) program. Trf1 deletion in kidneys led to fibrosis and EMT activation. Our findings suggest that telomere shortening or dysfunction may contribute to pathological, age-associated renal fibrosis by influencing the EMT program.

The mTOR pathway is necessary for survival of mice with short telomeres

Telomerase deficiency leads to age-related diseases and shorter lifespans. Inhibition of the mechanistic target of rapamycin (mTOR) delays aging and age-related pathologies. Here, we show that telomerase deficient mice with short telomeres (G2-Terc^−/−) have an hyper-activated mTOR pathway with increased levels of phosphorylated ribosomal S6 protein in liver, skeletal muscle and heart, a target of mTORC1. Transcriptional profiling confirms mTOR activation in G2-Terc^−/− livers. Treatment of G2-Terc^−/− mice with rapamycin, an inhibitor of mTORC1, decreases survival, in contrast to lifespan extension in wild-type controls. Deletion of mTORC1 downstream S6 kinase 1 in G3-Terc^−/− mice also decreases longevity, in contrast to lifespan extension in single S6K1^−/− female mice. These findings demonstrate that mTOR is important for survival in the context of short telomeres, and that its inhibition is deleterious in this setting. These results are of clinical interest in the case of human syndromes characterized by critically short telomeres.

Telomerase deficiency leads to age-related diseases and shortened lifespan, while inhibition of the mTOR pathway delays aging. Here, the authors show that inhibition of mTORC1 signaling shortens the lifespan of telomerase deficient mice.

Phloretin attenuates STAT-3 activity and overcomes sorafenib resistance targeting SHP-1-mediated inhibition of STAT3 and Akt/VEGFR2 pathway in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy. Phloretin (PH) possesses anticancer, antitumor, and hepatoprotective effects, however, the effects and potential mechanisms of phloretin remain elusive.

Methods

Five HCC cells were tested in vitro for sensitivity to PH, Sorafenib (Sor) or both and the apoptosis, signal transduction and phosphatase activity were analyzed. To validate the role of SHP-1, we used PTP inhibitor III and SHP-1 siRNA. Further, we used purified SHP-1 proteins or HCC cells expressing deletion N-SH2 domain or D61A point mutants to study the PH efficacy on SHP-1. The `in vivo studies were conducted using HepG2 and SK-Hep1 and Sor resistant HepG2^SR and Huh7^SR xenografts. Molecular docking was done with Swiss dock and Auto Dock Vina.

Results

PH inhibited cell growth and induced apoptosis in all HCC cells by upregulating SHP-1 expression and downregulating STAT3 expression and further inhibited pAKT/pERK signaling. PH activated SHP-1 by disruption of autoinhibition of SHP-1, leading to reduced p-STAT3^Tyr705 level. PH induced apoptosis in two Sor-resistant cell lines and overcome STAT3, AKT, MAPK and VEGFR2 dependent Sor resistance in HCCs. PH potently inhibited tumor growth in both Sor-sensitive and Sor-resistant xenografts in vivo by impairing angiogenesis, cell proliferation and inducing apoptosis via targeting the SHP-1/STAT3 signaling pathway.

Conclusion

Our data suggest that PH inhibits STAT3 activity in Sor-sensitive and -resistant HCCs via SHP-1–mediated inhibition of STAT3 and AKT/mTOR/JAK2/VEGFR2 pathway. Our results clearly indicate that PH may be a potent reagent for hepatocellular carcinoma and a noveltargeted therapy for further clinical investigations.

Graphical abstract

Electronic supplementary material

The online version of this article (10.1186/s12964-019-0430-7) contains supplementary material, which is available to authorized users.

Abstract 257: Dual targeting of PI3K/AKT and AR pathway by combination therapy with phloretin in pre-clinical and patient derived xenografts of enzalutamide-resistant prostate cancer

Background:

With the emergence of resistance to FDA-approved inhibitors of androgen receptor (AR) signaling in prostate cancer, AR remains a viable target, engaged in the regulation of processes of pathological importance. CRPC tumors adapt the PI3K/AKT survival pathway to escape ADT. Thus, co-targeting AR and PI3K/AKT signaling is more effective therapeutic means for CRPC patients. Phloretin (PH), is a polyphenolic compound, found in apples, cider etc. It is known to possess anticancer and anti-angiogenetic activity. However, it`s effect against CRPC cells and the underlying mechanism are still unknown.

Experimental procedure:

Ten human PCa cell lines were tested in vitro for sensitivity to the PI3K/AKT inhibitor LY294002; enzalutamide (ENZ); PH; LY294002 + PH; ENZ + PH and LY294002 + ENZ + PH. In vivo studies were conducted using VCaP, 22Rv1, MR49F xenografts and LuCaP and 136CR PCa PDX tumors. Molecular docking was done with AutoDock Vina program. CSF Chimera and Ligplot programs were used for analysis of ligand and proteins interactions.

Results:

LY294002; ENZ; PH; LY294002 + PH; ENZ + PH and LY294002 + ENZ + PH inhibited in vitro growth of 7 of 10; 9 of 10; 9 of 10; 9 of 10; 9 of 10; 10 of 10 PCa cell lines, respectively, with increased sensitivity under androgen depletion. PH inhibited tumor growth in VCaP, 22Rv1, MR49F, MR49C xenografts and LuCaP and 13CR PCa PDX in a dose-dependent manner. Further, dual combination of ENZ + PH was more effective than LY294002 + PH in inhibiting tumor growth, whereas LY294002 + ENZ + PH diminished the tumor growth (P<0.005) and demonstrated a longer disease specific survival. PH alone inhibited the AR-DNA interaction directly or by interfering with AR dimerization and inhibited AR-V7 expression and transcriptional activity. Further, it blocked the R1881 induced expression of AR-target genes kallikrein-related peptidase 3 (KLK3, also known as PSA); transmembrane protease, serine 2 (TMPRSS2); and FK506 binding protein 5 (FKBP5), glucocorticoid receptor (GR). In LuCaP PCa PDX tumors, PH administration decreased TV (P=0.021), proliferation (p=0.0024), PSA (p<0.005) and decreased AR signaling and nuclear glucocorticoid receptor (nGR) localization. Computer aided molecular docking data shows the binding affinity and ligand efficiency scores of PH in following chronological order: AR > AKT1 > GR > PI3K.

Conclusion:

Our studies suggested triple combination improved the efficacy of ENZ and PH. PH could be promising candidates for prevention of CRPC. This pre-clinical synergy provides a strong rationale for clinical evaluation of this combination.

Citation Format: Sarita Saraswati, Abdulqader A. Alhaider, Abdelgalil M. Abdelgadir. Dual targeting of PI3K/AKT and AR pathway by combination therapy with phloretin in pre-clinical and patient derived xenografts of enzalutamide-resistant prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 257.

Camel milk inhibits inflammatory angiogenesis via downregulation of proangiogenic and proinflammatory cytokines in mice

Camel milk has traditionally been used to treat cancer, but this practice awaits scientific scrutiny, in particular its role in tumor angiogenesis, the key step involved in tumor growth and metastasis. We aimed to investigate the effects of camel milk on key components of inflammatory angiogenesis in sponge implant angiogenesis model. Polyester-polyurethane sponges, used as a framework for fibrovascular tissue growth, were implanted in Swiss albino mice and camel milk (25, 50 and 100 mg/kg/day) was administered for 14 days through installed cannula. The implants collected at day 14 post-implantation were processed for the assessment of hemoglobin (Hb), myeloperoxidase (MPO), N-acetylglucosaminidase (NAG), and collagen, which were used as indices for angiogenesis, neutrophil, and macrophage accumulation and extracellular matrix deposition, respectively. Relevant inflammatory, angiogenic, and fibrogenic cytokines were also determined. Camel milk treatment attenuated the main components of the fibrovascular tissue, wet weight, vascularization (Hb content), macrophage recruitment (NAG activity), collagen deposition and the levels of vascular endothelial growth factor (VEGF), interleukin (IL)-1β, IL-6, IL-17, tumor necrosis factor-α, and transforming growth factor-β. A regulatory function of camel milk on multiple parameters of the main components of inflammatory angiogenesis has been revealed, giving insight into the potential therapeutic benefit underlying the anti-cancer actions of camel milk.

Ursolic acid inhibits tumor angiogenesis and induces apoptosis through mitochondrial-dependent pathway in Ehrlich ascites carcinoma tumor

Ursolic acid (UA) is a pentacyclic triterpene naturally occurring in many plant foods. In the present study, we investigated anti-cancer activity of UA in vivo in Ehrlich ascites carcinoma (EAC) tumor. 15 × 10(6) EAC cells were implanted intraperitoneally (i.p., ascitic tumor) and subcutaneous (s.c., solid tumor) in Swiss albino mice. Mice with established tumors received UA i.p. at 25, 50 and 100mg/kg bw for 14 d in ascitic and 100mg/kg bw in solid tumor for 30 d. On day 15, blood samples were collected for hematological assessment of hemoglobin (Hb%), RBCs, WBCs and PCV. Tumor volume, cell viability, angiogenic, anti-angiogenic, anti-inflammatory factors and antioxidant parameters were determined. Immunohistochemistry analysis for VEGF, iNOS, CD31, caspase-3 and Bax were also performed. UA significantly inhibited tumor growth, cell viability, in both ascites and solid tumor model in vivo (p<0.001). The anti-angiogenic effects were accompanied with decreased VEGF, iNOS, TNF-α and increased IL-12 levels. UA at 100mg/kg bw dose significantly increased SOD and CAT activity (p<0.01). GSH and TBARS were increased as compared to control group (p<0.001). Furthermore, UA increased total RBCs, WBCs as well as Hb% significantly (p<0.05) compared to cyclophosphamide (CP). Histopathological examination of tumor cells in the treated group demonstrated signs of apoptosis with chromatin condensation and cell shrinkage. Decreased peritoneal angiogenesis showed the anti-angiogenic potential. UA downregulated VEGF & iNOS expression whereas bax and caspase-3 expressions were upregulated suggesting drug induced tumor cell apoptosis through activating the pro-apoptotic bcl-2 family and caspase-3 and downregulation of VEGF. The present study sheds light on the potent antitumor property of the UA and can be extended further to develop therapeutic protocols for treatment of cancer.

Anticarcinogenic effect of brucine in diethylnitrosamine initiated and phenobarbital-promoted hepatocarcinogenesis in rats

We evaluated the effects of brucine on N-nitrosodiethylamine (DENA)-induced hepatocarcinogenesis in rats. Initiation of hepatocarcinogenesis was done by intraperitoneal injection of diethylnitrosamine (DENA) followed by promotion with phenobarbital. The rats were exposed to dietary brucine for 4 weeks prior to initiation, and the treatment was continued for 22 consecutive weeks. Brucine decreased the incidence, total number, multiplicity, size and volume of preneoplastic hepatic nodules in a dose-dependent manner. Administration of DENA induced hepatocellular carcinoma (HCC), as evidenced by changes in histopathological architecture, increased activity of cytochrome P450, decreased activity of glutathione Stransferase (GST) as well as decreased antioxidant status, enhanced lipid peroxidation, increased liver marker enzymes. Western blot analysis showed decreased expression of cyclin D1 and Bcl-2 with activation of caspase-3 and increased expression of Bax. Immunohistochemical demonstrated the decreased expression of the PCNA and VEGF. These results indicate that brucine prevents lipid peroxidation and hepatic cell damage and also protects the antioxidant system in DENA-induced hepatocarcinogenesis.

Tylophorine, a phenanthraindolizidine alkaloid isolated from Tylophora indica exerts antiangiogenic and antitumor activity by targeting vascular endothelial growth factor receptor 2-mediated angiogenesis

Background

Anti-angiogenesis targeting VEGFR2 has been considered as an important strategy for cancer therapy. Tylophorine is known to possess anti-inflammatory and antitumor activity, but its roles in tumor angiogenesis, the key step involved in tumor growth and metastasis, and the involved molecular mechanism is still unknown. Therefore, we examined its anti-angiogenic effects and mechanisms in vitro and in vivo.

Methods

We used tylophorine and analyzed its inhibitory effects on human umbilical vein endothelial cells (HUVEC) in vitro and Ehrlich ascites carcinoma (EAC) tumor in vivo.

Results

Tylophorine significantly inhibited a series of VEGF-induced angiogenesis processes including proliferation, migration, and tube formation of endothelial cells. Besides, it directly inhibited VEGFR2 tyrosine kinase activity and its downstream signaling pathways including Akt, Erk and ROS in endothelial cells. Using HUVECs we demonstrated that tylophorine inhibited VEGF-stimulated inflammatory responses including IL-6, IL-8, TNF-α, IFN-γ, MMP-2 and NO secretion. Tylophorine significantly inhibited neovascularization in sponge implant angiogenesis assay and also inhibited tumor angiogenesis and tumor growth in vivo. Molecular docking simulation indicated that tylophorine could form hydrogen bonds and aromatic interactions within the ATP-binding region of the VEGFR2 kinase unit.

Conclusion

Tylophorine exerts anti-angiogenesis effects via VEGFR2 signaling pathway thus, may be a viable drug candidate in anti-angiogenesis and anti-cancer therapies.

Proteomic identification of galectin-3 binding ligands and characterization of galectin-3 proteolytic cleavage in human prostasomes

Galectin-3 is a multifunctional carbohydrate-binding protein that was previously characterized as a proteolytic substrate for prostate-specific antigen (PSA) and was shown to be associated with prostasomes in human semen. Prostasomes are exosome-like vesicles that are secreted by the prostatic epithelium and have multiple proposed functions in normal reproduction and prostate cancer. In the current study, galectin-3 binding ligands in human prostasomes were identified and characterized with the goal to investigate galectin-3 function in prostasomes. Galectin-3 binding proteins were isolated by affinity column chromatography. Candidate ligands identified by MS/MS were PSA, prostatic acid phosphatase (PAP), zinc alpha-2-glycoprotein (ZAG), dipeptidyl peptidase-4 (CD26), aminopeptidase N (CD13), neprilysin, clusterin, antibacterial protein (FALL-39) and alpha-1-acid glycoprotein (ORM1). Biochemical methods were used to characterize the ability of galectin-3 to bind to selected ligands, and galectin-3 cleavage assays were utilized to investigate the protease(s) in prostasomes that cleaves galectin-3. CD26, CD13, PSA, PAP and ZAG immunoreactivity were detected in extracts of purified prostasomes. One-dimensional electroblot analysis of prostasomes demonstrated that CD26, PAP and CD13 immunoreactivity co-migrated with galectin-3-reactive protein bands. PSA and ZAG were found to be associated with the surface of prostasomes. Both intact and cleaved galectin-3 were detected in prostate and prostasome extracts. Cleavage and inhibition assays indicated that PSA in prostasomes proteolytically cleaves galectin-3. The identification of these glycoproteins as galectin-3 ligands lays the groundwork for future studies of galectin-3 and prostasome function in reproduction and prostate cancer.

Strychnine inhibits inflammatory angiogenesis in mice via down regulation of VEGF, TNF-α and TGF-β

Strychnine is known to possess anti-inflammatory and antitumour activity, but its roles in tumour angiogenesis, the key step involved in tumour growth and metastasis, and the involved molecular mechanism are still unknown. We aimed to investigate the effects of strychnine on key components of inflammatory angiogenesis in the murine cannulated sponge implant angiogenesis model. Polyester-polyurethane sponges, used as a framework for fibrovascular tissue growth, were implanted in Swiss albino mice and strychnine (0.25, and 0.5 mg/kg/day) was given through installed cannulas for 9 days. The implants collected at day 9 postimplantation were processed for the assessment of haemoglobin (Hb), myeloperoxidase (MPO), N-acetylglucosaminidase (NAG) and collagen used as indexes for angiogenesis, neutrophil and macrophage accumulation and extracellular matrix deposition, respectively. Relevant inflammatory, angiogenic and fibrogenic cytokines were also determined. Strychnine treatment attenuated the main components of the fibrovascular tissue, wet weight, vascularization (Hb content), macrophage recruitment (NAG activity), collagen deposition and the levels of vascular endothelial growth factor (VEGF), tumour necrosis factor (TNF)-α and transforming growth factor (TGF-β). A regulatory function of strychnine on multiple parameters of main components of inflammatory angiogenesis has been revealed giving insight into the potential therapeutic underlying the actions of strychnine.

Brucine, an indole alkaloid from Strychnos nux-vomica attenuates VEGF-induced angiogenesis via inhibiting VEGFR2 signaling pathway in vitro and in vivo

In this study, we investigated the mechanism of brucine in tumor angiogenesis. We found that brucine inhibits VEGF-induced cell proliferation, chemotactic motility, and the formation of capillary-like structures in HUVECs in a dose-dependent manner. Brucine suppresses VEGF- induced p-VEGFR2 kinase activity and inhibits neovascularization in vivo. Brucine inhibits the downstream protein kinases of VEGFR2, including Src, FAK, ERK, AKT and mTOR. And further downregulates levels of VEGF, NO, IL-6, IL-8, TNF-α and IFN-γ in HUVECs. Taken together, our study suggests that brucine potently suppresses angiogenesis by targeting VEGFR2 activation and may be a viable drug candidate in anti-angiogenesis and anti-cancer therapies.

Boswellic acid inhibits inflammatory angiogenesis in a murine sponge model

The aim of the present study was to investigate the effects of boswellic acid (BA) on key components of inflammatory angiogenesis in the murine cannulated sponge implant angiogenesis model. Polyester-polyurethane sponges, used as a framework for fibrovascular tissue growth, were implanted in Swiss albino mice and BA (12.5 or 25mg/kg/day) was given through installed cannulas for nine days. The implants collected at day 9 post-implantation were processed for the assessment of hemoglobin (Hb). Relevant levels of inflammatory, angiogenic and fibrogenic cytokines were also determined. BA treatment resulted in significant decrease in sponge vascularization (Hb content) and in vascular endothelial growth factor (VEGF) and transforming growth factor (TGF-β1) at both doses. Further, BA decreased expression of VEGF and CD31 and reduced % microvessel density (MVD) in sponge implants. A regulatory function of BA on multiple parameters of the main components of inflammatory angiogenesis has been revealed giving an insight into the potential therapeutic use underlying the actions of BA.

Antitumor properties of Boswellic acid against Ehrlich ascites cells bearing mouse

Boswellic acid (BA), a triterpene, isolated from Boswellia serrata (Burseraceae) has been found to possess potent anti-inflammatory and anti-cancer activity. The present study aimed at exploring the possible role of BA on ascites and solid Ehrlich tumor. Ascitic tumor development was evaluated 14 d after tumor implantation by quantification of the ascitic fluid volume whereas solid tumor was evaluated after 30 d tumor implantation by H&E and IHC. The i.p. administration of BA significantly inhibited ascitic and solid Ehrlich tumor model. This inhibition was observed with reduced ascitic volume, solid tumor volume and body weight when compared to control mice. The treatments also increased the survival of tumor-bearing mice. VEGF and TNF- α levels were decreased, whereas the IL-12 levels were increased with BA treatment at 25mg/kg. Further, results on decrease in the peritoneal angiogenesis and microvessel density showed the anti-angiogenic potential. Microscopic examination of tumors revealed that in BA-treated groups the expression of Bax and caspase 3 increased, suggesting drug induced tumor cell apoptosis through activating the pro-apoptotic bcl-2 family and caspase-3. The present study sheds light on the potent antitumor property of the boswellic acid and can be extended further to develop therapeutic protocols for treatment of cancer.

Development and evaluation of a latex agglutination test for rabies antibodies

BACKGROUND

The presently recommended tests for estimation of rabies neutralising antibodies like Rapid Fluorescent Focus Inhibition test (RFFIT) and Mouse Neutralisation test (MNT) are laborious, time consuming and not cost-effective for routine use. Simple, rapid and economical tests need to be developed for routine use.

OBJECTIVES

The main objective of the present study was to develop and evaluate a rapid Latex Agglutination Test (LAT) to detect rabies specific antibodies.

METHODS

Latex beads were coated with purified rabies glycoprotein at a concentration of 1 mg/ml followed by coating with 0.3% bovine serum albumin (BSA). These sensitised beads were used to detect antiglycoprotein antibodies in sera of 152 people who had taken a course of post exposure rabies vaccination with different cell culture vaccines and whose antibody titers were pre determined by MNT. Sera from 52 normal healthy people without any detectable levels of rabies antibodies were included as controls. The test was carried out on glass slides by mixing 20 micro l of sensitised beads and 20 micro l serum.

RESULTS

Preliminary evaluation with rabbit serum of known potency indicated that for clear agglutination of sensitised beads, a minimum of 2 IU/ml of rabies antibody should be present in the serum samples. Visible agglutination was noticed in positive sera with a titer > or =2 IU/ml within 3-5 min after mixing. Seven Sera whose MNT titers were less than 2 IU/ml did not show agglutinati or n. None of the negative control sera showed agglutination. Thus the specificity of the test was 100% and sensitivity was 95.4%.

CONCLUSIONS

The LAT described here detects rabies specific antibodies > or =2 IU/ml and can be used to screen large number of sera from vaccinated people to know the protective status after vaccination. This simple and rapid test may be used routinely in antirabies treatment centres to monitor sero conversion in vaccinated people.

A passive haemagglutination test for rabies antibodies using rabies glycoprotein coupled erythrocytes

The presently recommended tests for assaying rabies antibodies like mouse neutralization test (MINT) and rapid fluorescent focus inhibition test (RFFIT) are either time consuming or expensive and are generally performed in reference laboratories. There is a need to develop a specific and rapid method for detection of rabies antibodies that can be used to monitor sero-conversion after pre-or post-exposure vaccination. In this study, we have developed a passive haemagglutination (PHA) using purified rabies virus glycoprotein coupled to sheep erythrocytes using chromium chloride (0.04%) as a coupling agent. Two hundred and fifty five serum samples from people vaccinated with different rabies vaccines, 16 paired serum and CSF samples from autopsy confirmed cases of paralytic rabies, and serum samples from 65 normal healthy controls were tested and evaluated in comparison to standard MNT. Among the vaccinees, 250 samples were positive both by MNT and PHA but 5 samples were negative by PHA and positive by MNT. The titres obtained by PHA were lower compared to MNT, but there was significant correlation between the two (r=0.885). The specificity of the test was 99.7% and sensitivity was 100% as compared to MNT. Thus this PHA test promises to be a rapid and specific test for assaying rabies antibodies and may be useful in screening large number of serum samples for sero conversion after vaccination. It may also assist in rapid laboratory confirmation of paralytic rabies cases, based on detection of antibodies in CSF and serum.

Comparative evaluation of a simple indirect immunofluorescence test and mouse neutralization test for assaying rabies antibodies

In this study, we have developed and evaluated a simple indirect immunofluorescence test (IIFT) to detect rabies antibodies in a two-step immunofluorescence assay. One hundred and eighty five serum samples from people who had taken different rabies vaccines and 8 pairs of serum and CSF samples from confirmed paralytic rabies cases were tested by IIFT and results evaluated in comparison to standard mouse neutralization test (MNT). Though the titres of rabies antibodies obtained with IIFT were 2-4 times lesser in comparison to MNT, a significant correlation was seen between the two tests (R = 0.883). The specificity of this IIFT was found to be 97.9% and the sensitivity was 97.2%. These results indicate that this simple and rapid IIFT can be used to screen large number of serum samples to monitor sero-conversion after pre or post exposure vaccination and may also assist in rapid ante-mortem diagnosis of atypical human rabies.