Longitudinal Follow-Up of the Immunity to SARS-CoV-2 in Health Care Workers in Argentina: Persistence of Humoral Response and Neutralizing Capacity after Sputnik V Vaccination.

SARS-CoV-2 vaccine protection has encountered waning of immune response and breakthrough infections. The hybrid immune response generated by the combination of vaccination and infection was shown to offer higher and broader protection. Here, we present a seroprevalence study of anti-SARS-CoV-2 spike/RBD IgG in 1,121 health care workers immunized with Sputnik V and a follow-up of humoral response at 2 and 24 weeks postvaccination (wpv), including neutralizing antibody response (NAT) against ancestral, Gamma, and Delta variants. The first seroprevalence study showed that among 122 individuals with one dose, 90.2% were seropositive versus 99.7% seropositivity among volunteers with the complete two-dose regimen. At 24 wpv, 98.7% of the volunteers remained seropositive, although antibody levels decreased. IgG levels and NAT were higher in individuals that had acquired COVID-19 previous to vaccination than in naive individuals at 2 and 24 wpv. Antibody levels dropped over time in both groups. In contrast, IgG levels and NAT increased after vaccine breakthrough infection. At 2 wpv, 35/40 naive individuals had detectable NAT against SARS-CoV-2 Gamma and 6/40 against Delta. In turn, 8/9 previously infected individuals developed a neutralizing response against SARS-CoV-2 Gamma and 4/9 against Delta variants. NAT against variants followed a trajectory similar to NAT against ancestral SARS-CoV-2, and breakthrough infection led to an increase in NAT and complete seroconversion against variants. In conclusion, Sputnik V-induced humoral response persisted at 6 months postvaccination, and hybrid immunity induced higher levels of anti-S/RBD antibodies and NAT in previously exposed individuals, boosted the response after vaccination, and conferred wider breadth of protection. IMPORTANCE Since December 2020, Argentina has begun a mass vaccination program. The first vaccine available in our country was Sputnik V, which has been approved for use in 71 countries with a total population of 4 billion people. Despite all the available information, there are fewer published studies on the response induced by Sputnik V vaccination compared to that of other vaccines. Although the global political context has paralyzed the verification by the WHO of the efficacy of this vaccine, our work aims to add new clear and necessary evidence to Sputnik V performance. Our results contribute to general knowledge of the humoral immune response developed by vaccines based on viral vector technology, highlighting the higher immune protection conferred by hybrid immunity and reinforcing the importance of completing vaccination schedules and booster doses to maintain adequate antibody levels.

Strategic approach to produce low-cost, efficient, and stable competitive internal controls for detection of RNA viruses by use of reverse transcription-PCR.

Molecular diagnostics based on reverse transcription (RT)-PCR are routinely complicated by the lack of stable internal controls, leading to falsely negative results. We describe a strategy to produce a stable competitive internal control (CIC) based on a Qbeta phage derivative (recombinant Qbeta [rQbeta]) bearing primers KY78 and KY80, which are widely used in the detection of hepatitis C virus (HCV). rQbeta was RNase resistant and stable at 4 degrees C for 452 days in SM medium (0.1 M NaCl, 8 mM MgSO(4).7H(2)O, 50 mM Tris HCl [pH 7.5], 2% gelatin) and for 125 days after lyophilization and reconstitution. rQbeta performance as a CIC was evaluated. rQbeta was added to HCV-positive samples, followed by RNA extraction and a CIC-HCV RT-PCR assay. This method combines RT-PCR, liquid hybridization with nonradioactive probes, and enzyme immunoanalysis. No influence of the CIC on qualitative HCV detection was observed independently of viral load, and results had high concordance with those of commercial kits. In conclusion, we describe a versatile, low-cost alternative strategy to armored RNA technology that can be adapted for detection or real-time applications of any RNA target. Moreover, the CIC reported here is an essential reagent for HCV screening in blood banks in resource-limited settings.

[Development of slides for Epstein-Barr virus diagnosis by indirect immunofluorescence]. / Desarrollo de improntas para el diagnóstico del virus Epstein-Barr por inmunofluorescencia indirecta.

Epstein-Barr virus (EBV) is the main oncogenic lymphotropic agent of the Herpesviridae family and is globally distributed. EBV acute infection occurs in young adults producing infectious mononucleosis. Detection of anti-viral capside antigen (VCA) antibodies indicates previous or present EBV infection. Moreover, high titles of anti-VCA antibodies are observed in EBV-associated neoplasic disorders, such as lymphomas in AIDS patients. The objective of this study was the development and optimization of P3HR1 cell slides for the EBV serologic detection by indirect immunofluorescence (IIF) assay. P3HR1 exponential growth culture cells were stimulated with phorbol-12-mirystoil-13-acetate, collected at different time points and used for slide preparation. IIF assay was performed in each slide using an anti-EBV positive serum as primary antibody. An 11% increase in VCA expression was observed at 40 hours post-stimulation. Data was confirmed by Western blot and immunodetection. Intra- and inter-lot precisions of the developed slides were evaluated for IgG and IgM antibodies using EBV-positive sera and positive samples for other members of the Herpesviridae family. Neither false-positive or false negative results were obtained for EBV detection nor cross-reaction was observed with other members of the Herpesviridae family with the developed slides. In conclusion, the slides here presented can be a useful instrument for acute EBV infection diagnosis and for the serologic detection of IgG anti-VCA antibodies in EBV-associated neoplastic disorders.

Desarrollo de improntas para el diagnóstico del virus Epstein-Barr por inmunofluorescencia indirecta. / [Development of slides for Epstein-Barr virus diagnosis by indirect immunofluorescence]

Epstein-Barr virus (EBV) is the main oncogenic lymphotropic agent of the Herpesviridae family and is globally distributed. EBV acute infection occurs in young adults producing infectious mononucleosis. Detection of anti-viral capside antigen (VCA) antibodies indicates previous or present EBV infection. Moreover, high titles of anti-VCA antibodies are observed in EBV-associated neoplasic disorders, such as lymphomas in AIDS patients. The objective of this study was the development and optimization of P3HR1 cell slides for the EBV serologic detection by indirect immunofluorescence (IIF) assay. P3HR1 exponential growth culture cells were stimulated with phorbol-12-mirystoil-13-acetate, collected at different time points and used for slide preparation. IIF assay was performed in each slide using an anti-EBV positive serum as primary antibody. An 11

increase in VCA expression was observed at 40 hours post-stimulation. Data was confirmed by Western blot and immunodetection. Intra- and inter-lot precisions of the developed slides were evaluated for IgG and IgM antibodies using EBV-positive sera and positive samples for other members of the Herpesviridae family. Neither false-positive or false negative results were obtained for EBV detection nor cross-reaction was observed with other members of the Herpesviridae family with the developed slides. In conclusion, the slides here presented can be a useful instrument for acute EBV infection diagnosis and for the serologic detection of IgG anti-VCA antibodies in EBV-associated neoplastic disorders.

[Non conventional virological markers in HIV-infected patients: T-HIV DNA, 2LTR-HIV DNA and HIV RNA]. / Marcadores virológicos no convencionales en pacientes infectados con el virus de la inmunodeficiencia humana: ADN HIV-T, ADN HIV-2LTR y ARN de HIV.

Highly active antiretroviral therapy (HAART) induces a persistent reduction of the plasmatic viremia, contributing to decrease mortality and morbidity of infected people with human immunodeficiency virus (HIV). Thus, viral load (VL) is the reference method to evaluate therapy effectiveness. However, even in the presence of efficient HAART viral eradication was yet not achieved. In this study, we analyzed the presence of total HIV DNA (T-HIV DNA), non-integrated DNA with 2LTR (2LTR-HIV DNA) and HIV RNA in a group of 55 HIV-positive subjects from Rosario City, with different clinical stages, with and without HAART. All markers were evaluated by PCR assays optimized in our laboratory that included colorimetric detection in microplate. HIV RNA clinical sensitivity was compared with a reference test, bDNA, resulting in 74% and 64% respectively, with an 85% of agreement. Thus, our HIV RNA assay could be used to monitor patients under HAART and at risk of infection. The 2LTR-HIV DNA was 54% positive although it was absent in patients with high VL. This marker was considered a labile product therefore its presence was associated with recent infection. However, current evidences question its stability. Thus, its clinical significance should be reconsidered. The absence of 2LTR-HIV DNA in patients with detectable VL may relate to the heterogeneity of the sequence used for its detection. T-HIV DNA was present in 100% of the samples and could be a relevant remission marker when therapies that effectively eradicate the infection became available.

Reversible cholestasis induced by experimental partial obstruction of the bile duct; Biochemical, morphometric and hepatic transport kinetic studies.

The aim of this investigation was to reproduce in rats a partial stenosis of the common bile duct to analyze early liver functional and morphometric changes. The hepatic transport kinetics of sulfobromophthalein (organic anion) and rhodamine B (organic cation) was also investigated, and compartmental analysis of both compounds was performed. The humoral parameters of liver function indicated a cholestasis after 2 days of surgery, which reverted to reach normal values on the seventh day. Tumor necrosis factor alpha serum levels showed a tendency to increase on the second day of stenosis (7 out of 14 rats) while white blood cells increased on the second day of stenosis, and turned to normal levels on the seventh day. Histological studies showed increased volume of portal areas and ductular proliferation, which did no revert during the time of the study (up to 7 days post-op). Conversely, a moderate fibrosis and leukocyte infiltrates in portal areas predominated on the second day of stenosis, but normalized on the seventh day. Bile flow was considerably diminished on the second day of partial obstruction as compared to controls. The mean recovery in bile of sulfobromophthalein after 1h of being injected was low on the second day of stenosis, but normalized on the seventh day. Conversely, that of rhodamine B was very low in all animals. Sulfobromophthalein kinetics showed that hepatic uptake and canalicular excretion were impaired during the second but normalized on the seventh day of stenosis. However, rhodamine B kinetics showed that this compound was poorly excreted in all groups although canalicular excretion increased on the second day. The results suggested a model of obstructive cholestasis induced by the experimental stenosis of the bile duct which was not only reversible but also implicates the role of hepatic inflammation.

Marcadores virológicos no convencionales en pacientes infectados con el virus de la inmunodeficiencia humana: ADN HIV-T, ADN HIV-2LTR y ARN de HIV. / [Non conventional virological markers in HIV-infected patients: T-HIV DNA, 2LTR-HIV DNA and HIV RNA]

Highly active antiretroviral therapy (HAART) induces a persistent reduction of the plasmatic viremia, contributing to decrease mortality and morbidity of infected people with human immunodeficiency virus (HIV). Thus, viral load (VL) is the reference method to evaluate therapy effectiveness. However, even in the presence of efficient HAART viral eradication was yet not achieved. In this study, we analyzed the presence of total HIV DNA (T-HIV DNA), non-integrated DNA with 2LTR (2LTR-HIV DNA) and HIV RNA in a group of 55 HIV-positive subjects from Rosario City, with different clinical stages, with and without HAART. All markers were evaluated by PCR assays optimized in our laboratory that included colorimetric detection in microplate. HIV RNA clinical sensitivity was compared with a reference test, bDNA, resulting in 74

and 64

respectively, with an 85

of agreement. Thus, our HIV RNA assay could be used to monitor patients under HAART and at risk of infection. The 2LTR-HIV DNA was 54

positive although it was absent in patients with high VL. This marker was considered a labile product therefore its presence was associated with recent infection. However, current evidences question its stability. Thus, its clinical significance should be reconsidered. The absence of 2LTR-HIV DNA in patients with detectable VL may relate to the heterogeneity of the sequence used for its detection. T-HIV DNA was present in 100

of the samples and could be a relevant remission marker when therapies that effectively eradicate the infection became available.

Marcadores virologicos no convencionales en pacientes infectados con el virus de la inmunodeficiencia humana: ADN HIV-T, ADN HIV-2LTR y ARN de HIV / Non conventional virological markers in HIV-infected patients: T-HIV DNA, 2LTR-HIV DNA and HIV RNA

La terapia antirretrovial de alta eficacia (TAAE) induce una reducción marcada y persisatente de la viremia plasmática, contribuvendo a disminuir la mortalidad de los pacientes HIV-positivos. Así, la carga viral (CV) es el método de referencia para evaluar la eficacia terapéutica. Sin embargo, aun en presencia de una TAAE eficiente no se ha logrado la erradicación viral. En este estudio analizamos la presencia del ADN total de HIV (ADN HIV-T), del ADN no integrado con 2LTR (ADN HIV-2LTR) y del ARN de HIV, en un grupo de 55 pacientes HIV-positivos en distintos estadios clínicos, con y sin TAAE, mediante ensayos de PCR con revelado colorimétrico en microplaca, optimizados en nuestro laboratorio. La sensibilidad clínica de ARN del HIV fue evaluada con el bDNA, resultando del 74% y del 64%, respectivamente, con una concordancia del 85%. Este ensayo podría utilizado en el seguimiento de pacientes bajo TAAE. EI ADN HIV-2LTR resultó positivo en el 54% aunque estuvo ausente en pacientes con elevada CV. Este marcador se considereba un producto lábil y su presencia se asociaba a infección reciente. Sin embargo, actuales evidencias ponen en discusión su estabilidad por lo que su significado clínico debe ser reconsiderado. La ausencia del ADN HIV-2LTR en pacientes con CV detectable puede relacionarse con la heterogeneidade de la secuencia utilizada para su detección. EI ADN HIV-T estuvo presente en el 100% de las muestras y resultaría relevante como marcador de remisión cuando se dispongan de terapias que efectivamente erradiquen la infección. (AU)

Marcadores virologicos no convencionales en pacientes infectados con el virus de la inmunodeficiencia humana: ADN HIV-T, ADN HIV-2LTR y ARN de HIV / Non conventional virological markers in HIV-infected patients: T-HIV DNA, 2LTR-HIV DNA and HIV RNA

La terapia antirretrovial de alta eficacia (TAAE) induce una reducción marcada y persisatente de la viremia plasmática, contribuvendo a disminuir la mortalidad de los pacientes HIV-positivos. Así, la carga viral (CV) es el método de referencia para evaluar la eficacia terapéutica. Sin embargo, aun en presencia de una TAAE eficiente no se ha logrado la erradicación viral. En este estudio analizamos la presencia del ADN total de HIV (ADN HIV-T), del ADN no integrado con 2LTR (ADN HIV-2LTR) y del ARN de HIV, en un grupo de 55 pacientes HIV-positivos en distintos estadios clínicos, con y sin TAAE, mediante ensayos de PCR con revelado colorimétrico en microplaca, optimizados en nuestro laboratorio. La sensibilidad clínica de ARN del HIV fue evaluada con el bDNA, resultando del 74% y del 64%, respectivamente, con una concordancia del 85%. Este ensayo podría utilizado en el seguimiento de pacientes bajo TAAE. EI ADN HIV-2LTR resultó positivo en el 54% aunque estuvo ausente en pacientes con elevada CV. Este marcador se considereba un producto lábil y su presencia se asociaba a infección reciente. Sin embargo, actuales evidencias ponen en discusión su estabilidad por lo que su significado clínico debe ser reconsiderado. La ausencia del ADN HIV-2LTR en pacientes con CV detectable puede relacionarse con la heterogeneidade de la secuencia utilizada para su detección. EI ADN HIV-T estuvo presente en el 100% de las muestras y resultaría relevante como marcador de remisión cuando se dispongan de terapias que efectivamente erradiquen la infección.

Prevalencia de infección por el virus de la hepatitis C en mujeres embarazadas inmunocompetentes: análisis de la transmisibilidad madre-hijo y seguimiento de un neonato aparentemente infectado / Prevalence of hepatitis C virus infection in immunocompetent pregnant women: analysis of mother-to-infant transmission and follow up of an apparently infected newborn

En el período comprendido entre marzo de 1998 y abril de 1999 se investigó la presencia de anticuerpos anti hepatitis C (VHC) en 276 mujeres embarazadas inmunocompetentes (HIV 1 y 2 no reactivas). Se observó una seroprevalencia del 0,72 por ciento (2/276). En uno de los dos niños nacidos de madres infectadas se realizó un protocolo de seguimiento para verificar la transmisibilidad del virus. A lo largo de un año se observaron en el neonato aminotransferasas normales, siendo indetectables anticuerpos anti VHC y RNA de VHC hacia el sexto y noveno mes de vida, respectivamente. El genotipo observado en madre e hijo fue el 2 b (AU)

Prevalencia de infección por el virus de la hepatitis C en mujeres embarazadas inmunocompetentes: análisis de la transmisibilidad madre-hijo y seguimiento de un neonato aparentemente infectado / Prevalence of hepatitis C virus infection in immunocompetent pregnant women: analysis of mother-to-infant transmission and follow up of an apparently infected newborn

En el período comprendido entre marzo de 1998 y abril de 1999 se investigó la presencia de anticuerpos anti hepatitis C (VHC) en 276 mujeres embarazadas inmunocompetentes (HIV 1 y 2 no reactivas). Se observó una seroprevalencia del 0,72 por ciento (2/276). En uno de los dos niños nacidos de madres infectadas se realizó un protocolo de seguimiento para verificar la transmisibilidad del virus. A lo largo de un año se observaron en el neonato aminotransferasas normales, siendo indetectables anticuerpos anti VHC y RNA de VHC hacia el sexto y noveno mes de vida, respectivamente. El genotipo observado en madre e hijo fue el 2 b

Síndrome anticuerpo antifosfolípido: cómo llegamos a su diagnóstico? / Anti-phosppholipid antibody syndrome: how do we arrive to its diagnosis?

Nuestro objetivo es presentar un razonamiento diagnóstico para la detección del síndrome anticuerpo antifosfolípido, teniendo en cuenta las variadas manifestaciones cutáneas del mismo. La sintomatología clínica, la biopsia de piel, el análisis hematológico e inmunológico incluyendo anticuerpos anticardiolipinas y el estudio de la coagulación constituyen la metodología para llegar al diagnóstico de certeza del síndrome. Las manifestaciones clínicas más relevantes son trombosis arteriales y venosas en cualquier segmento del árbol vascular y abortos recurrentes. Además puede presentar cefaleas e hipertensión arterial. Hacemos hincapié en el estudio de coagulación, sus pruebas de selección (APTT-dRVVT-TCK) y la detección de anticuerpos anticardiolipinas por enzimoinmunoanálisis (AU)

Síndrome anticuerpo antifosfolípido: cómo llegamos a su diagnóstico? / Anti-phosppholipid antibody syndrome: how do we arrive to its diagnosis?

Nuestro objetivo es presentar un razonamiento diagnóstico para la detección del síndrome anticuerpo antifosfolípido, teniendo en cuenta las variadas manifestaciones cutáneas del mismo. La sintomatología clínica, la biopsia de piel, el análisis hematológico e inmunológico incluyendo anticuerpos anticardiolipinas y el estudio de la coagulación constituyen la metodología para llegar al diagnóstico de certeza del síndrome. Las manifestaciones clínicas más relevantes son trombosis arteriales y venosas en cualquier segmento del árbol vascular y abortos recurrentes. Además puede presentar cefaleas e hipertensión arterial. Hacemos hincapié en el estudio de coagulación, sus pruebas de selección (APTT-dRVVT-TCK) y la detección de anticuerpos anticardiolipinas por enzimoinmunoanálisis