16 Embryo aggregation and adipose-derived mesenchymal donor cells in bovine somatic cell nuclear transfer

Somatic cell nuclear transfer (SCNT) is a powerful tool, but its efficiency remains low. The use of less differentiated donor cells or the embryo aggregation (EA) strategy improves the SCNT rates in several species. It remains unexplored whether the combined use of both strategies results in a synergistic effect that improves SCNT efficiency in bovine. To evaluate that, we assessed the optimal time of EA using IVF embryos (aim 1) and we evaluated whether the use of adipose-derived mesenchymal stem cells (ASC) as donor for SCNT together with EA improves the blastocyst rates and quality (aim 2). For aim 1, cumulus–oocyte complexes (COCs) were collected from slaughterhouse ovaries, invitro matured (TCM-199), fertilized (16×106 spermatozoa mL−1 for 5h) and cultured (synthetic oviductal fluid media in a humidified gas mixture at 39°C). After IVF, the zona pellucida was enzymatically removed and zona-free (ZF) embryos were cultured individually (1X) or 2 embryos placed together within a microwell (2X) (Day 0, n=70). This procedure was performed at Days 3, 4, 5, 6, or 7 (n=76, 78, 94, 96, 90, respectively) and blastocyst rate was assessed at Day 8. Contribution of both embryos to the 2X blastocyst was confirmed by staining Day 0 IVF embryos either with green or red Mitotracker (ThermoFisher Scientific) before EA. For aim 2, fibroblast (FB) and ASC cells were isolated from the skin and subcutaneous adipose tissue of the same adult animal, respectively. Cloned embryos were produced by ZF enucleation, fusion of one ASC or FB cell, and activation with 5μM ionomycin/6-(dimethylamino)purine (6DMAP). After activation, cloned embryos were aggregated (FB2X or ASC2X) or individually cultured (FB1X or ASC1X). Blastocyst rates were recorded at Day 7 of invitro culture. Three biological replicates were evaluated for each aim. Embryo developmental differences were determined using Fisher’s exact test. Relative expression of OCT4, SOX2, and KRT18 was measured by RTqPCR at the blastocyst stage and analysed by Kruskal–Wallis statistical test. Regarding aim 1, no differences for developmental rates were found for Day 0, 3, 4, and 5 groups (57%, 60%, 61.5%, 61%), but the blastocyst rate was only improved in Day 0 and Day 3 relative to their respective 1X controls (Day 0 2X 54.2% vs. Day 0 1X 25.5% and Day 3 2X 52.6% vs. Day 3 1X 25.3%). No aggregation occurred in Day 6 and Day 7 groups. All blastomeres were homogeneously distributed in the 2X blastocyst. Regarding aim 2, no effect of the donor cell was observed on the blastocyst rate (FB1X 26.8%, n=82; ASC1X 21.7%, n=198; FB2X 39.7%, n=126; ASC2X 33%, n=204), whereas EA improved the blastocyst rate of ASC-derived embryos (ASC1X 21.7% vs. ASC2X 33%). Overall, no synergistic effect of the use of both strategies was observed. Relative expression of KRT18 was significantly different between ASC1X and ASC2X embryos. Although OCT4 and SOX2 expression did not differ between groups, EA tended to bring the values closer to that of an IVF embryo. No effect of the donor cell was observed on the embryo relative expression. Our results suggest that EA at Day 0 improves the blastocyst rate in bovine SCNT and IVF embryos. EA of 2 ASC-derived embryos seemed to normalise the embryo quality and may improve post-implantation development.

60 CRISPR-on, a new tool for activation of endogenous gene expression in bovine embryos

The CRISPR-Cas9 system enables precise genome editing in mammalian somatic cells and embryos at a very high efficiency. A modified version of Cas9 (dCas9) was engineered, resulting in a DNA binding protein capable of site-specific target recognition but unable to cut the DNA. By means of dCas9 fusion to heterologous domains, including transcriptional activators or repressors, specific modulation of gene expression has successfully been achieved invitro, making possible the modulation of the cell-differentiation state. However, CRISPR-mediated transcriptional activation (CRISPR-on) has been mainly used invitro, and to our knowledge, there are no reports regarding its use for the activation of endogenous gene expression in mammalian embryos. As a proof of principle, we evaluated the CRISPR-on system in bovine embryos for modulation of endogenous expression of SMARCA4 and TFAP2C, transcription factors implicated in trophoblast lineage commitment. We hypothesised that CRISPR-on may induce SMARCA4 or TFAP2C endogenous expression, enabling the design of strategies to induce trophectoderm proliferation of invitro-derived embryos. To this aim, we designed and synthesised 4 non-overlapping single guide RNAs to target the regulatory region of each of these target genes. Presumptive zygotes were cytoplasmically microinjected with a mix containing dCas9-VP160 mRNA and a pool of 4 single guide RNAs targeting SMARCA4 (dCas9_SM group) or TFAP2C (dCas9_TF group). As control, a non-injected group was also included. Analysis was carried out in pools of 10 early embryos or 5 blastocysts and at least 3 biological replicates were included. Gene expression was assessed by RTqPCR at Days 2, 4, and 7 after microinjection and data were normalized to that obtained for the non-injected group. The CRISPR-on system was efficient to induce expression of SMARCA4 two days after microinjection (dCas9_SM group, Mann-Whitney t-test; P<0.05), but failed to significantly increase TFAP2C expression (dCas9_TF group). Surprisingly, CDX2, which is a downstream effector for trophectoderm maintenance, was induced both in dCas9_SM and dCas9_TF groups, supporting the CRISPR-mediated induction of targeted transcription factors. However, no changes were observed in the endogenous level of NANOG. Additional analysis is currently ongoing to determine whether CRISPR-on mediated induction of SMARCA4 and/or TFAP2C expression affects lineage specification and regulation. To our knowledge, this is the first report on the use of CRISPR-on for modulation of endogenous gene expression in mammalian embryos. Our study lays the foundations for CRISPR-on application in embryos as a useful tool to understand key cell fate decisions and will enable unprecedented studies of significance to embryo development, cell differentiation, and segregation.

19 Improvement of the developmental competence of bovine somatic cell nuclear transfer embryos using latrunculin A during activation

Somatic cell nuclear transfer (SCNT) is an assisted reproductive technology with potential for its application in agriculture, biomedicine, and biotechnology. However, the SCNT efficiency is low. Failure in embryo production by SCNT could be associated mainly with chemical activation treatments or the donor cell type. In this context, we compare the use of latrunculin A (LatA), instead of cytochalasin B during the activation with roscovitine (Rosco), versus the treatment of donor cells with demecolcine (D-cells) followed by activation just with Rosco to compare cloning efficiency. The aim of this study was to evaluate the invitro developmental competence as well as the gene expression pattern of key genes (CDX2, OCT4, SOX2, and NANOG) in blastocysts obtained from the two treatments. To do this, cumulus-oocyte complexes were collected from cow ovaries obtained from slaughterhouses and were IVM for 21h. After cumulus-cell removal, enucleation was performed as described by Gambini et al. (2014 PLoS ONE 9, e110998; https://doi.org/10.1371/journal.pone.0110998). The G0/G1 cells or D-cells were fused to the oocytes. For activation, reconstructed zygotes were treated with 5μM ionomycin for 4min followed by 5-h incubation into different randomly activation groups: D-cells + 50μM Rosco (SCNT-Demec), G0/G1 cells + 50μM Rosco/10μM LatA (SCNT-LatA), and G0/G1 cells + 50μM Rosco/5μgmL−1 cytochalasin B (SCNT-Ctrol). Parthenogenetic controls were also included: Part-Demec, Part-LatA, and Part-Ctrol. Activated oocytes were cultured in synthetic oviductal fluid with amino acids medium until blastocyst stage. Rates of cleavage, morulae, and blastocysts were evaluated at Days 2, 5, and 7 of invitro culture, respectively. Relative abundance of mRNA coding for the four genes was compared between SCNT-Demec, SCNT-LatA, SCNT-Ctrol, and IVF groups by RTqPCR. Data was analysed by Fisher's exact test for invitro culture (P<0.05) or by one-way analysis of variance followed by Tukey post-hoc test (P=0.05). Cleavage rates from SCNT-Demec (n=247, 88%) and SCNT-LatA (n=112, 88%) were significantly higher than those from SCNT-Ctrol (n=123, 76%; Table 1). However, higher blastocyst rates were observed for the SCNT-LatA (n=112, 29%) group than for SCNT-Demec (n=247, 10%) and SCNT-Ctrol (n=123, 14%) (P<0.05). No differences were found for the relative abundance of mRNAs coding for SOX2 and CDX2 between all groups. The NANOG expression was significantly decreased in SCNT-Ctrol and SCNT-LatA compared with IVF embryos (P<0.05). The SCNT-Demec group did not differ from IVF embryos, and OCT4 expression analysis showed no difference among groups. In conclusion, LatA activation improved significantly blastocyst rates, whereas it did not affect gene expression when compared with IVF embryos. Our results suggest that this group could improve full-term developmental efficiency of SCNT embryos. Table 1.Cleavage, morulae, and blastocyst rates among the groups Group1 Treatment n Cleavage (%) Morulae (%) Blastocyst (%) SCNT-Demec Rosco 247 218 (88,26)b 41 (16,60)a 24 (9,72)a SCNT-Ctrol CB/Rosco 123 93 (75,61)a 25 (20,33)a 17 (13,82)a SCNT-LatA LatA 10μM/Rosco 112 99 (88,39)b 42 (37,50)b 33 (29,46)bc Part-Demec Rosco 141 133 (94,33)b 35 (24,82)a 20 (14,18)a Part-Ctrol CB/Rosco 84 76 (90,48)b 22 (26,19)ab 19 (22,62)ab Part-LatA LatA 10μM/Rosco 73 67 (91,78)b 30 (41,10)b 28 (38,36)c a-cStatistical differences between treatments (Fisher's test P<0.05). 1Treatments: donor cells with demecolcine (D-cells) + 50μM roscovitine (Rosco) (SCNT-Demec), G0/G1 cells + 50μM Rosco/10μM latrunculin A (LatA) (SCNT-LatA), and G0/G1 cells + 50μM Rosco/5μgmL−1 cytochalasin B (CB) (SCNT-Ctrol). Parthenogenetic controls were also included: Part-Demec, Part-LatA, and Part-Ctrol.

[Acute disseminated encephalomyelitis due to Mycoplasma pneumoniae in a previously healthy boy]

We present here the case of a previously healthy 5 year-old boy hospitalized in an intensive care unit due to tonic-clonic seizures focused on the face and right side of the body, and axillary temperature of 37.4°C. Common bacterial and viral etiology was ruled out through studies of cerebrospinal fluid (CSF) samples. Mycoplasma pneumoniae was suspected by a positive immunofluorescence serum test for IgM class antibodies. Finally, with a brain biopsy, M. pneumoniae was confirmed by polymerase chain reaction (PCR) and acute disseminated encephalomyelitis by pathological anatomy. The patient was treated with clarithromycin and had an uneventful evolution. At least to our knowledge, this is the first case in which M. pneumoniae DNA was detected by PCR in a brain biopsy.

202 Combination of transcription activator-like effector nucleases and homology-independent target integration strategy gene editing technologies for knock-in of recombinant human factor IX Under the β-casein native promoter in bovine IVF embryos

Precise DNA modification is a crucial approach for gene function elucidation, biomedical model development, and transgenic bioreactor generation. In livestock, its application was extremely challenging until the development of engineered nucleases such as zinc-finger nucleases, transcription activator-like effector nucleases (TALEN), and CRISPR/Cas9. Still, precise knock-in (KI) techniques remain inefficient. Recently, the homology-independent target integration (HITI) strategy was developed, allowing precise insertion of transgenes in mammalian cells in an easier fashion. The HITI technique allows site-specific gene insertion by means of cleavage of both the target sequence in the genome and the donor plasmid, followed by DNA repair by nonhomologous end joining. Here, we evaluated the use of TALENs to generate precise knockout (KO) alleles of the β-casein gene (CSN2) by creating small insertions or deletions, and precise insertion of recombinant human factor IX (rhFIX) under bovine CSN2 regulatory sequences, using HITI via cytoplasmic injection of bovine IVF zygotes. First, 2 TALEN pairs (Tn1 and Tn2) targeting exon 2 of bovine CSN2 were designed and their activity was confirmed by primary fibroblasts transfection followed by Surveyor assay at Day 3. Then, both TALEN pairs were evaluated for KO embryo generation by zygote cytoplasmic injection of in vitro-transcribed mRNA encoding for Tn1, Tn2, or a mix containing Tn1+Tn2, at 100ng μL−1. A non-injected control (NIC) was also included. Embryos were in vitro cultured until Day 7 and independently analysed by whole-genome amplification followed by PCR and sequencing. Neither the blastocyst rate [28.8% (n=73), 33.8% (n=71), 32.4% (n=74), and 54.3% (n=127) for Tn1, Tn2, Tn1+Tn2, and NIC, respectively] nor the proportion of edited embryos [44% (n=9), 20% (n=10), and 33% (n=9) for Tn1, Tn2, and Tn1+Tn2, respectively] differed between injected groups (Fisher test, P<0.05), demonstrating efficient editing in bovine embryos by TALENs. Finally, to achieve precise CSN2 KI embryos, the rhFIX open reading frame was PCR amplified with a forward primer containing the Tn1 recognition sequence to obtain the HITI donor and bovine IVF zygotes were co-injected with the Tn1 mRNA and the HITI donor. Embryos were in vitro cultured until Day 7 and individually analysed by nested PCR at both the 5′ and 3′ ends of HITI donor. The PCR-based results indicate HITI donor integration in 7% of embryos analysed (n=14). Sanger sequencing analysis is currently in progress to confirm site-specific integration of HITI and possible rearranged DNA integration in other embryos. To our knowledge, this is the first report on the use of TALEN and HITI for gene modification. Our results indicate that TALEN combined with HITI may constitute an easy strategy for precise production of pharmaceuticals in the milk of livestock.

Timing of respiratory syncytial virus and influenza epidemic activity in five regions of Argentina, 2007-2016

Background

Within‐country differences in the timing of RSV and influenza epidemics have not been assessed in Argentina, the eighth largest country in the world by area.

Objective

We aimed to compare seasonality for RSV and influenza both nationally and in each of the five regions to inform Argentina’s prevention and treatment guidelines.

Method

The Argentine National Laboratories and Health Institutes Administration collected respiratory specimens from clinical practices, outbreak investigations, and respiratory virus surveillance in 2007‐2016; these were tested using immunofluorescence or RT‐PCR techniques. We calculated weekly percent positive (PP) and defined season onset as >2 consecutive weeks when PP exceeded the annual mean for the respective year and region. Median season measures (onset, offset and peak) and the established mean method were calculated for each virus.

Results

An annual median 59 396 specimens were tested for RSV and 60 931 for influenza; 21–29% tested positive for RSV and 2–7% for influenza. National RSV activity began in April; region‐specific start weeks varied by 7 weeks. Duration of RSV activity did not vary widely by region (16–18 weeks in duration). National influenza activity started in June; region‐specific start weeks varied by 3 weeks. Duration of influenza epidemic activity varied more by region than that of RSV (7–13 weeks in duration).

Conclusion

In Argentina, RSV and influenza activity overlapped during the winter months. RSV season tended to begin prior to the influenza season, and showed more variation in start week by region. Influenza seasons tended to vary more in duration than RSV seasons.

199 Efficient Knock-out of Ovine β-Lactoglobulin (BLG) Gene and Knock-in of Recombinant Human Factor IX (rhFIX) Under BLG Native Regulatory Sequences in Somatic Cells and Zygotes Using TALEN Nuclease

Site-specific genetic engineering is a valuable tool for pharmaceutical research and development of biomedical models. Despite engineered nucleases allow targeted gene edition in a rather simple fashion; few reports are available so far on specific gene knock-in (KI) combined with engineered nucleases in domestic species. Here, we evaluated the possibility of inducing specific KI of cDNAs coding for proteins of pharmaceutical interest under the control of milk native promoter sequences, taking advantage of the TALEN system, both in ovine somatic cells and in zygotes. We designed 2 TALENs, targeting exons 1 and 5 of ovine β-lactoglobulin gene (BLG), respectively, and a homologous recombination vector (pHR), carrying recombinant human factor IX (rhFIX) flanked by homology arms contiguous to the TALEN target sites. In an initial set of experiments, 5 × 105 to 1 × 106 ovine fibroblasts were transfected with 1 μg of each TALEN mRNA, with or without 50 ng μL−1 pHR. The feasibility of inducing knock-out (KO) was confirmed by Cel1 assay. The deletion of the genomic region between TALEN target sites and the occurrence of HR in cell lysates were assessed by PCR. Also, 576 individual colonies were picked up and analyzed by PCR. The deletion of the region between TALEN target sites was achieved with 7.8% efficiency (45/576). The incidence of HR in cells was 0.5% (3/576), as detected by PCR. In order to evaluate the system in zygotes, laparoscopic AI was performed on synchronized and superovulated ewes. Zygotes were recovered 16 h after AI and cytoplasmically injected with (1) 5 ng μL−1 TALEN mix (2.5 ng μL−1 oaBLG T1.1 + 2.5 ng μL−1 oaBLG T5.1) (5TM); (2) 5 ng μL−1 TALEN mix + 25 ng μL−1 pHR-hFIX plasmid (5TM+25pRH); or (3) 15 ng μL−1 TALEN mix (7.5 ng μL−1 oaBLG T1.1 + 7.5 ng μL−1 oaBLG T5.1) + 50 ng μL−1 pHR-hFIX (15TM+50pRH). A non-injected control (NIC) was also included. Embryo analysis was conducted on whole-genome amplified DNA from blastocysts, followed by PCR and sequencing. Non-parametric Fisher test was applied to detect significant differences among treatments. Although blastocyst rates for NIC and 5TM did not statistically differ, 5TM+25pRH and 15TM+50pRH groups resulted in lower blastocysts rates than the NIC [P < 0.05; 13/17 (76%), 6/15 (40%), 4/15 (26%) and 2/14 (14%) for NIC, 5TM, 5TM+25pRH and 15TM+50pRH respectively]. It was possible to detect the PCR product compatible with deletion of the entire region among TALEN target sites in 6/6 blastocysts (100%) from the group 5TM, 3/4 blastocysts (75%) from the group 5TM+25pRH and 2/2 (100%) blastocysts from the group 15TM+50pRH. HR was detected in 1/2 (50%) blastocysts injected with 15TM+50pRH and in 1/4 (25%) blastocysts injected with 5TM+25pRH, by PCR and sequencing of the PCR products. Our results indicate that TALEN combined with homologous recombination constitutes a powerful platform for the production of proteins of pharmaceutical interest under native regulatory sequences in the milk of genetically modified animals.

Assessing Tn5 and Sleeping Beauty for transpositional transgenesis by cytoplasmic injection into bovine and ovine zygotes

Transgenic domestic animals represent an alternative to bioreactors for large-scale production of biopharmaceuticals and could also provide more accurate biomedical models than rodents. However, their generation remains inefficient. Recently, DNA transposons allowed improved transgenesis efficiencies in mice and pigs. In this work, Tn5 and Sleeping Beauty (SB) transposon systems were evaluated for transgenesis by simple cytoplasmic injection in livestock zygotes. In the case of Tn5, the transposome complex of transposon nucleic acid and Tn5 protein was injected. In the case of SB, the supercoiled plasmids encoding a transposon and the SB transposase were co-injected. In vitro produced bovine zygotes were used to establish the cytoplasmic injection conditions. The in vitro cultured blastocysts were evaluated for reporter gene expression and genotyped. Subsequently, both transposon systems were injected in seasonally available ovine zygotes, employing transposons carrying the recombinant human factor IX driven by the beta-lactoglobulin promoter. The Tn5 approach did not result in transgenic lambs. In contrast, the Sleeping Beauty injection resulted in 2 lambs (29%) carrying the transgene. Both animals exhibited cellular mosaicism of the transgene. The extraembryonic tissues (placenta or umbilical cord) of three additional animals were also transgenic. These results show that transpositional transgenesis by cytoplasmic injection of SB transposon components can be applied for the production of transgenic lambs of pharmaceutical interest.

35 USE OF METAPHASE DONOR CELLS AND ACTIVATION WITH ROSCOVITINE FOR SOMATIC CELL NUCLEAR TRANSFER IN BOVINE

Cloning of domestic species by somatic cell nuclear transfer (SCNT) continues to be inefficient, probably due to an incomplete reprogramming of the reconstituted embryo. The ability of the embryonic cytoplasm to support reprogramming fluctuates within the cell cycle (Egli et al. 2007 Nature 447, 679–85). In this context, we compared the development capability and second polar body (2PB) extrusion of embryos produced by metaphase (M) cells, in comparison with G0/G1 cells, which are commonly used as nuclear donors. Because M cells have 2 sets of chromosomes (in contrast with G0/G1 cells, which have only 1 set), an activation protocol that impedes 2PB extrusion is required to produce reconstituted embryos with the correct ploidy. Therefore, we performed SCNT with M or G0/G1 cells, followed by different activation protocols, and evaluated in vitro development and 2PB extrusion of the reconstituted embryos. Cow oocytes were in vitro matured and enucleated as described by Gambini et al. (2014 PLoS One 14, 9). A group of cells at 70 to 80% confluence was synchronized in M stage using 0.05 μg mL−1 demecolcine for 3 to 4 h and used as nuclear donors for SCNT (M group). Another group of cells was induced into quiescence by serum starvation for 3 to 4 days before SCNT (G0/G1 group). For activation, reconstituted embryos were treated with 5 µM ionomycin (Io) for 4 min followed by 5-h incubation in 50 μM roscovitine for M group, or in 50 μM roscovitine and 5 μg mL−1 cytochalasin B for G0/G1 group. Parthenogenetic controls were activated with Io followed by 50 μM roscovitine alone (ROSCO) or with 5 μg mL−1 cytochalasin B (ROSCO/CB). Hoescht 33342 staining was performed 16 h post-Io to evaluate 2PB extrusion. Other activated oocytes were cultured in SOFaa medium and rates of cleavage, morulas, and blastocysts were evaluated at Days 2, 5 and 7 of in vitro development, respectively. Data were analysed by Fisher’s exact test (P < 0.05). Rates of 2PB extrusion were 72.72 (n = 33), 65.63 (n = 32), 80 (n = 15), and 42.86 (n = 14) for M, G0/G1, ROSCO, and ROSCO/CB, respectively. Results of in vitro development are shown in Table 1. In conclusion, somatic M cells can be used as donors to produce cloned embryos. The M and G0/G1 groups were able to induce cloned blastocysts, even though rates did not differed statistically from controls groups (ROSCO and ROSCO/CB). The M group was as effective as G0/G1. Although further analysis is required to establish the quality of the embryos, our results are encouraging for use in SCNT. Table 1.In vitro development of NT embryos produced with M and G0/G1 donor cells

Efficient edition of the bovine PRNP prion gene in somatic cells and IVF embryos using the CRISPR/Cas9 system

The recently developed engineered nucleases, such as zinc-finger nucleases, transcription activator-like effector nucleases, and clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated nuclease (Cas) 9, provide new opportunities for gene editing in a straightforward manner. However, few reports are available regarding CRISPR application and efficiency in cattle. Here, the CRISPR/Cas9 system was used with the aim of inducing knockout and knock-in alleles of the bovine PRNP gene, responsible for mad cow disease, both in bovine fetal fibroblasts and in IVF embryos. Five single-guide RNAs were designed to target 875 bp of PRNP exon 3, and all five were codelivered with Cas9. The feasibility of inducing homologous recombination (HR) was evaluated with a reporter vector carrying EGFP flanked by 1 kbp PRNP regions (pHRegfp). For somatic cells, plasmids coding for Cas9 and for each of the five single-guide RNAs (pCMVCas9 and pSPgRNAs) were transfected under two different conditions (1X and 2X). For IVF zygotes, cytoplasmic injection was conducted with either plasmids or mRNA. For plasmid injection groups, 1 pg pCMVCas9 + 0.1 pg of each pSPgRNA (DNA2X) was used per zygote. In the case of RNA, two amounts (RNA1X and RNA2X) were compared. To assess the occurrence of HR, a group additionally cotransfected or coinjected with pHRegfp plasmid was included. Somatic cell lysates were analyzed by polymerase chain reaction and surveyor assay. In the case of embryos, the in vitro development and the genotype of blastocysts were evaluated by polymerase chain reaction and sequencing. In somatic cells, 2X transfection resulted in indels and large deletions of the targeted PRNP region. Regarding embryo injection, higher blastocyst rates were obtained for RNA injected groups (46/103 [44.6%] and 55/116 [47.4%] for RNA1X and RNA2X) than for the DNA2X group (26/140 [18.6%], P < 0.05). In 46% (26/56) of the total sequenced blastocysts, specific gene editing was detected. The total number of genetic modifications (29) was higher than the total number of gene-edited embryos, as three blastocysts from the group RNA2X reported more than one type of modification. The modifications included indels (10/56; 17.9%) and large deletions (19/56; 33.9%). Moreover, it was possible to detect HR in 1/8 (12.5%) embryos treated with RNA2X. These results report that the CRISPR/Cas9 system can be applied for site-specific edition of the bovine genome, which could have a great impact on the development of large animals resistant to important zoonotic diseases.

243 EFFICIENT EDITION OF THE BOVINE PRNP PRION GENE IN SOMATIC CELLS AND IVF EMBRYOS USING THE CLUSTERED REGULARLY INTERSPACED SHORT PALINDROMIC REPEATS (CRISPR)/Cas9 SYSTEM

The rapid introduction of engineered nucleases technologies, such as zinc finger nucleases (ZFN), transcription activator-like effector nucleases (TALEN) and clustered regularly interspaced short palindromic repeats (CRISPR), provides new opportunities for editing genes in a targeted and rather simple fashion. Few reports are available regarding CRISPR efficiency in domestic species. Here, the CRISPR/Cas9 system was employed to develop knockout and knock-in alleles of the bovine PRNP gene, responsible for bovine spongiform encephalopathy (mad cow disease), both in bovine fetal fibroblasts and in IVF embryos. Five sgRNAs were designed to target a 875-bp region within prnp exon 3; all 5 were co-delivered with hCas9 and a homologous recombination vector carrying gfp (pHRegfp). For cells, 3 transfection conditions were compared: 2 μg of hCas9 + 1 μg of sgRNAs mix ± 2 μg pHREGFP (1X) versus 4 μg of hCas9 + 2 μg of sgRNAs mix ± 4 μg of pHREGFP (2X). For IVF zygotes, cytoplasmic injection was conducted with 2 RNA concentrations: (a) 50 ng μL–1 hCas9 RNA + 25 ng μL–1 sgRNAs mix (RNA1X), ±50 ng μL–1 pHREGFP, and (b) 100 ng μL–1 hCas9 + 50 ng μL–1 sgRNAs mix (RNA2X), ±100 ng μL–1 pHREGFP, which were compared with plasmid injections with 100 ng μL–1 pCMVCas9 + 50 ng μL–1 pU6sgRNAs mix (DNA2X), ±100 ng μL–1 pHREGFP. The pHREGFP was always injected as plasmid, under the same conditions as hCas9. DNA from cells was subjected to PCR, Surveyor assay, and sequence analysis. Embryo analysis was conducted on whole-genome-amplified DNA from blastocysts, followed by PCR assays and sequencing. In cells, 2X transfection resulted in indels and amplification of PCR products of lower MW than the wild-type, indicative of the deletion of a part of the targeted PRNP region. However, it was not possible to detect an effect for 1X transfection. For the group transfected with pHREGFP, insertion of a partial EGFP sequence was detected (383 bp). Regarding embryo injection, higher blastocyst rates were obtained in all groups injected with RNA (Table 1). In 48% (21/43) of the sequenced blastocysts specific gene editing was detected (Table 1). Modifications varied among single base pair shift (3/43; 7%), high level of mismatches all over the targeted sequence and vicinity (12/43; 27.9%), full deletion of the 875-bp region (1/43; 2.3%), and partial insertion of 100–498 bp pHREGFP fragments between the HR arms (5/24; 20.8%). Most of these modifications occurred in a mosaic fashion (76%). Results demonstrate that CRISPR/Cas can be efficiently applied for site-specific edition of domestic species genomes. Table 1.In vitro development and gene editing efficiency of embryos injected with plasmids or RNA coding for CRISPR/Cas9 system targeting PRNP

242 HIGHLY EFFICIENT SLEEPING BEAUTY TRANSPOSON-MEDIATED TRANSGENESIS IN BOVINE FETAL FIBROBLASTS

Active transposon-mediated transgenesis is an emerging tool for basic and applied research in livestock. We have demonstrated the effectiveness of a helper-independent piggyBac transposon (pGENIE-3) for gene transfer into the genome of bovine cells (Alessio et al. 2014 Reprod. Domest. Anim. 49, 8). Here, we extend our previous research by examining the suitability of a Sleeping Beauty (SB) transposon-based methodology to deliver transgenes into the genome of bovine fetal fibroblasts (BFF), and the ability of these cells to support in vitro embryo development upon somatic cell nuclear transfer (SCNT). In a first experiment, BFF were chemically cotransfected (JetPRIME®, Polyplus-transfection, Illkirch, France) with a helper plasmid (pCMV-SB100X), which carries an expression cassette for the SB transposase, and the donor vector (pT2/Venus/RMCE) harboring an expression cassette for a fluorescent protein (Venus) flanked by the SB inverted terminal repeats (ITR). Three different ratios of helper and donor plasmids were studied: 1 : 2, 1 : 1 and 2 : 1. After 15 days of culture, the number of fluorescent colonies was counted on an inverted microscope. When vectors were used at ratios of 1 : 1 and 2 : 1, a 78-fold and 88-fold increase (P ≤ 0.05) in the number of fluorescent colonies compared with that in the no-transposase control were calculated. In a second experiment, BFF were chemically cotransfected with the helper vector pCMV-SB100X, and 2 donor transposons: pT2/Venus/RMCE and pT2/SV40-Neo. The former harbors a neo resistance cassette framed by SB ITRs. Different ratios of helper:donors (1 : 1 : 1, 2 : 1 : 1 and 2 : 0.5 : 0.5) were studied, and each ratio compared with a no-transposase control. After 15 days of antibiotic selection, the number of G418-resistant colonies was determined. Every time a functional SB transposase vector was included, the number of fluorescent and G418-resistant colonies was markedly higher compared with that in the respective control without transposase (P ≤ 0.001). Interestingly, all G418-resistant colonies expressed Venus. Molecular characterisation of genomic insertions in 6 monoclonal cell lines was performed by PCR and splinkerette PCR. PCR analysis confirmed presence of the Venus transgene in all cell lines. Splinkerette PCR results revealed at least 15 transposase-catalyzed genomic insertions of the transgene. Individual cells from a polyclonal SB transgenic fibroblast culture were used as nuclear donors to produce zona-free SCNT embryos. Of the reconstructed embryos, 33% reached blastocyst stage and about half of them expressed Venus. In conclusion, SB transposase is able to actively transpose monomeric copies of transgenes into the genome of bovine cells, which can be reprogrammed upon nuclear transfer to generate morphologically normal embryos expressing the transgene of interest.

Systematic review and meta-analysis of respiratory syncytial virus infection epidemiology in Latin America

Respiratory syncytial virus (RSV) is a frequent cause of acute respiratory infection and the most common cause of bronchiolitis in infants. The aim of this systematic review and meta-analysis was to obtain a comprehensive epidemiological picture of the data available on disease burden, surveillance, and use of resources in Latin America. Pooled estimates are useful for cross-country comparisons. Data from published studies reporting patients with probable or confirmed RSV infection in medical databases and gray literature were included from 74 studies selected from the 291 initially identified. When considering all countries, the largest pooled percentage RSV in low respiratory tract infection patients was found in the group between 0 and 11 months old, 41.5% (95% CI 32.0–51.4). In all countries, percentages were increasingly lower as older children were included in the analyses. The pooled percentage of RSV in LRTIs in the elderly people was 12.6 (95% CI 4.2–24.6). The percentage of RSV infection in hospitalized newborns was 40.9% (95% CI 28.28–54.34). The pooled case fatality ratio for RSV infection was 1.74% (95% CI 1.2–2.4) in the first 2 years of life. The average length of stay excluding intensive care unit admissions among children with risk factors for severe disease was 12.8 (95% CI 8.9–16.7) days, whereas it averaged 7.3 (95% CI 6.1/8.5) days in otherwise healthy children.We could conclude that infants in their first year of age were the most vulnerable population. To our knowledge, this is the first systematic review on RSV disease burden and use of health resources in Latin America.

Burden of influenza in Latin America and the Caribbean: a systematic review and meta-analysis

OBJECTIVE

Influenza causes severe morbidity and mortality. This systematic review aimed to assess the incidence, etiology, and resource usage for influenza in Latin America and the Caribbean.

DESIGN

Meta-analytic systematic review. Arcsine transformations and DerSimonian Laird random effects model were used for meta-analyses.

SETTING

A literature search from 1980 to 2008 in MEDLINE, Cochrane Library, EMBASE, LILACS, Ministries of Health, PAHO, proceedings, reference lists, and consulting experts.

SAMPLE

We identified 1092 references, of which 31 were finally included, in addition to influenza surveillance reports. We also used information from the 10 reports from the collaborative group for epidemiological surveillance of influenza and other respiratory virus (GROG), and information retrieved from the WHO global flu database FLUNET.

MAIN OUTCOME MEASURES

Incidence, percentage of influenza specimens out of the total received by influenza centers and resource-use outcomes.

RESULTS

A total of 483 130 specimens of patients with influenza were analyzed. Meta-analysis showed an annual rate of 36 080 (95%CI 28 550 43 610) influenza-like illness per 100 000 persons-years. The percentage of influenza out of total specimens received by influenza centers ranged between 4.66% and 15.42%, with type A the most prevalent, and A subtype H3 predominating. The mean length of stay at hospital due to influenza ranged between 5.8 12.9 days, total workdays lost due to influenza-like illnesses were 17 150 days, and the mean direct cost of hospitalization was US$575 per laboratory-confirmed influenza case.

CONCLUSIONS

Our data show that seasonal influenza imposes a high morbidity and economic burden to the region. However, the vaccine-uptake rate has been low in this region. Population-based cohort studies are required to improve the knowledge about incidence and resource utilization, which would inform healthcare authorities for decision making.

Addition of the immunostimulatory oligonucleotide IMT504 to a seasonal flu vaccine increases hemagglutinin antibody titers in young adult and elder rats, and expands the anti-hemagglutinin antibody repertoire

Flu vaccines are partially protective in infants and elder people. New adjuvants such as immunostimulatory oligonucleotides (ODNs) are strong candidates to solve this problem, because a combination with several antigens has demonstrated effectiveness. Here, we report that IMT504, the prototype of a major class of immunostimulatory ODNs, is a potent adjuvant of the influenza vaccine in young adult and elderly rats. Flu vaccines that use virosomes or whole viral particles as antigens were combined with IMT504 and injected in rats. Young adult and elderly animals vaccinated with IMT504-adjuvated preparations reached antibody titers 20-fold and 15-fold higher than controls, respectively. Antibody titers remained high throughout a 120 day-period. Animals injected with the IMT504-adjuvated vaccine showed expansion of the anti-hemagglutinin antibody repertoire and a significant increase in the antibody titer with hemagglutination inhibition capacity when confronted to viral strains included or not in the vaccine. This indicates that the addition of IMT504 in flu vaccines may contribute to the development of significant cross-protective immune response against shifted or drifted flu strains.

Epidemiologic and virologic assessment of the 2009 influenza A (H1N1) pandemic on selected temperate countries in the Southern Hemisphere: Argentina, Australia, Chile, New Zealand and South Africa

Please cite this paper as: Van Kerkhove et al. (2011) Epidemiologic and virologic assessment of the 2009 influenza A (H1N1) pandemic on selected temperate countries in the Southern Hemisphere: Argentina, Australia, Chile, New Zealand and South Africa. Influenza and Other Respiratory Viruses 5(6), e487–e498.

Introduction and Setting  Our analysis compares the most comprehensive epidemiologic and virologic surveillance data compiled to date for laboratory‐confirmed H1N1pdm patients between 1 April 2009 ‐ 31 January 2010 from five temperate countries in the Southern Hemisphere–Argentina, Australia, Chile, New Zealand, and South Africa.

Objective  We evaluate transmission dynamics, indicators of severity, and describe the co‐circulation of H1N1pdm with seasonal influenza viruses.

Results  In the five countries, H1N1pdm became the predominant influenza strain within weeks of initial detection. South Africa was unique, first experiencing a seasonal H3N2 wave, followed by a distinct H1N1pdm wave. Compared with the 2007 and 2008 influenza seasons, the peak of influenza‐like illness (ILI) activity in four of the five countries was 3‐6 times higher with peak ILI consultation rates ranging from 35/1,000 consultations/week in Australia to 275/100,000 population/week in New Zealand. Transmission was similar in all countries with the reproductive rate ranging from 1.2–1.6. The median age of patients in all countries increased with increasing severity of disease, 4–14% of all hospitalized cases required critical care, and 26–68% of fatal patients were reported to have ≥1 chronic medical condition. Compared with seasonal influenza, there was a notable downward shift in age among severe cases with the highest population‐based hospitalization rates among children <5 years old. National population‐based mortality rates ranged from 0.8–1.5/100,000.

Conclusions  The difficulty experienced in tracking the progress of the pandemic globally, estimating its severity early on, and comparing information across countries argues for improved routine surveillance and standardization of investigative approaches and data reporting methods.

Severe pandemic 2009 H1N1 influenza disease due to pathogenic immune complexes

Pandemic influenza viruses often cause severe disease in middle-aged adults without preexisting comorbidities. The mechanism of illness associated with severe disease in this age group is not well understood. Here we find preexisting serum antibodies that cross-react with, but do not protect against, 2009 H1N1 influenza virus in middle-aged adults. Nonprotective antibody is associated with immune complex-mediated disease after infection. We detected high titers of serum antibody of low avidity for H1-2009 antigen, and low-avidity pulmonary immune complexes against the same protein, in severely ill individuals. Moreover, C4d deposition--a marker of complement activation mediated by immune complexes--was present in lung sections of fatal cases. Archived lung sections from middle-aged adults with confirmed fatal influenza 1957 H2N2 infection revealed a similar mechanism of illness. These observations provide a previously unknown biological mechanism for the unusual age distribution of severe cases during influenza pandemics.

Pediatric hospitalizations associated with 2009 pandemic influenza A (H1N1) in Argentina

BACKGROUND

While the Northern Hemisphere experiences the effects of the 2009 pandemic influenza A (H1N1) virus, data from the recent influenza season in the Southern Hemisphere can provide important information on the burden of disease in children.

METHODS

We conducted a retrospective case series involving children with acute infection of the lower respiratory tract or fever in whom 2009 H1N1 influenza was diagnosed on reverse-transcriptase polymerase-chain-reaction assay and who were admitted to one of six pediatric hospitals serving a catchment area of 1.2 million children. We compared rates of admission and death with those among age-matched children who had been infected with seasonal influenza strains in previous years.

RESULTS

Between May and July 2009, a total of 251 children were hospitalized with 2009 H1N1 influenza. Rates of hospitalization were double those for seasonal influenza in 2008. Of the children who were hospitalized, 47 (19%) were admitted to an intensive care unit, 42 (17%) required mechanical ventilation, and 13 (5%) died. The overall rate of death was 1.1 per 100,000 children, as compared with 0.1 per 100,000 children for seasonal influenza in 2007. (No pediatric deaths associated with seasonal influenza were reported in 2008.) Most deaths were caused by refractory hypoxemia in infants under 1 year of age (death rate, 7.6 per 100,000).

CONCLUSIONS

Pandemic 2009 H1N1 influenza was associated with pediatric death rates that were 10 times the rates for seasonal influenza in previous years.

Pandemic flu: from the front lines. Interviewed by Declan Butler

Researchers describe the scientific and public-health challenges they face in battling the H1N1 virus.

Surveillance of adamantane resistance among influenza A H3 viruses isolated in Argentina between 2001 and 2007

A dramatic rise in the frequency of resistance to adamantane drugs by influenza A H3 viruses, associated with a single amino acid replacement in the viral matrix M2 protein, has occurred in multiple countries worldwide in recent years. We investigated the frequency of adamantane-resistant influenza A H3 viruses in Argentina during the period 2001-2007. We used reverse transcription followed by polymerase chain reaction. The obtained products were sequenced for the detection of mutations of the M2 gere relevant to the resistance phenotypes. The HA1 sequences of the sensitive and resistant strains were also analyzed to clarify whether they had any relevance to the resistant mutations. Twenty out of 55 (36%) strains were identified with the resistance-conferring substitution at amino acid 31 (Serine 31 Asparagine). No resistant viruses were detected between 2001 and 2005. All strains isolated in 2006 and four out of five isolates from 2007 were resistant. None of the patients had received previous treatment with amantadine and/or rimantadine. The HA1 analysis showed that there were only two changes (Serine193 Phenylalanine and Aspartic acid 225 Asparagine) present in the strains with the M2 substitution at position 31. Our data indicate that since 2006 there has been a significant increase of adamantane-resistant influenza A H3 viruses, which raises concern over the spread of these viruses in Argentina.

Detection of respiratory viruses and subtype identification of influenza A viruses by GreeneChipResp oligonucleotide microarray

Acute respiratory infections are significant causes of morbidity, mortality, and economic burden worldwide. An accurate, early differential diagnosis may alter individual clinical management as well as facilitate the recognition of outbreaks that have implications for public health. Here we report on the establishment and validation of a comprehensive and sensitive microarray system for detection of respiratory viruses and subtyping of influenza viruses in clinical materials. Implementation of a set of influenza virus enrichment primers facilitated subtyping of influenza A viruses through the differential recognition of hemagglutinins 1 through 16 and neuraminidases 1 through 9. Twenty-one different respiratory virus species were accurately characterized, including a recently identified novel genetic clade of rhinovirus.

[Influenza associated excess mortality in Argentina: 1992-2002]

OBJECTIVE

To describe the effect of influenza on mortality in Argentina, from 1992 to 2002.

METHOD

In order to fulfill this objective, influenza associated excess mortality was determined by the application of ARIMA method to mortality data for pneumonia and influenza and for all causes.

RESULTS

Excess mortality was only detected during subtype A/H3N2 seasons. The model yielded about 31,240 excess mortality for all causes. Pneumonia deaths contributed in about 15%. Approximately 80-95% of pneumonia and influenza excess mortality was restricted to persons > 64 years old.

CONCLUSIONS

These estimations show that the virus circulation has had an important influence on mortality, increasing the number of deaths, especially in elderly population. The aging of the population reinforces the need of preventing strategies, including vaccination programs with high coverage in elderly population.

[Effect of influenza epidemics on mortality in Santa Fe, Argentina, during 1992-1999]

OBJECTIVES

To define the effect of influenza epidemics on mortality and to establish the best criterion for predicting mortality so as to provide a method for advance warning of the severity of an influenza epidemic.

METHODS

The study was carried out in La Capital, a department in Santa Fe province, Argentina, during 1992-1999. In order to fulfill the first objective, a retrospective analysis was performed with mortality data for pneumonia and influenza in persons over 65 years of age, using the auto-regressive integrated moving averages (ARIMA). The latter were used to determine the excess mortality attributable to influenza epidemics. In order to attain the second objective, a regression analysis was performed so as to study the correlation between weekly morbidity from influenza and monthly mortality from pneumonia or influenza in personas over 65. Morbidity was expressed in terms of three summary measures which were derived from the number of cases of influenza that were reported during the first 35 weeks of the year: the sum total of all cases reported weekly, their standard deviation, and the maximum number of cases in any given week. We included in the analysis the type and subtype of influenza. These four parameters (type and subtype of influenza, along with one of the three summary measures) were compared among themselves in terms of their ability to explain the mortality observed during the first eight months of the year.

RESULTS

Epidemics occurred during the winters of 1993, 1995, and 1999 and in the spring of 1997. During those seasons, excess deaths were observed in connection with the circulation of a predominant strain of influenza virus, type A (H3N2). There were no epidemics in the winter months of 1994, 1996, and 1998, despite the circulation of this viral strain. During the winters in which influenza virus strains A (H1N1) and B were in circulation (1992 and 1997, respectively) - both are associated with low mortality figures - no excess deaths were detected.

CONCLUSIONS

The number of weekly cases of influenza reported during the peak of the winter season is the best criterion for predicting how much excess mortality can be attributed to the epidemic.

Regional perspectives on influenza surveillance in South America

The implementation of influenza vaccination programs emphasize the necessity of an extended influenza surveillance in the countries of the region. As it is based on the activity of National Influenza Centers we intend to make a description of their work, their historical background and further development. Technical capacities in influenza South America laboratories, and networks in Argentina, Brazil and Chile are shown. Examples of different viral circulation in a unique country or in countries with common borders illustrate the importance of the information obtained by means of the virological surveillance. Specific characteristics of the region as long distances and the lack of modern information systems require a suitable fitting of the systems that are working in Northern Hemisphere countries. The contribution of motivated physicians and public health workers must not to be disregarded. The following actions are proposed: optimizing technical capacities of National Influenza Centers in order to improve the quality of data available; improving the communication of the information obtained by surveillance activities to all the participants; increasing the cooperation among the countries; motivate health authorities to become aware of influenza impact in public health.

Multicentered study of viral acute lower respiratory infections in children from four cities of Argentina, 1993-1994

This study describes the first multicentered study of acute lower respiratory infection viral etiology in young children from four different geographical areas of Argentina. A total of 1,278 children under 5 years of age, hospitalized in primary care centers from Buenos Aires, Córdoba, Santa Fé and Mar del Plata cities during a 2-year period were studied (1993-1994). Nasopharyngeal aspirates were investigated for respiratory syncytial virus (RSV), adenovirus, parainfluenza, and influenza A and B viruses by indirect immunofluorescence. Out of the patients studied, 946 (74%) were under 1 year of age. Viruses were detected in 399 patients (32%). RSV was observed in 25.3% of the samples, representing 78.2% of all viral positive cases. Adenoviruses were detected in 2.5% of the cases, parainfluenza in 2.2%, influenza A in 2.1%, and influenza B in 0.2%. Compared with other viruses, the higher RSV frequency was statistically significant (P < 0.000). Most RSV cases were detected between May and September with a significant peak in July (P < 0.000). Pneumonia was observed in 46% of the patients, bronchiolitis in 41% and other entities in 13%. The case fatality rate observed during the 2 year study was 0.73%. Most of the above respiratory viruses were detected in the four cities, however, the frequency of RSV and influenza were different in the southern city.

Genetic characterization of wild-type measles viruses isolated during the 1998 measles epidemic in Argentina

This study reports on genomic characterization of six measles virus (MV) isolates obtained from a measles epidemic in Argentina in 1998. Reverse transcription-polymerase chain reaction (RT-PCR) and nucleotide sequence analysis of the carboxyl-terminal region of the nucleoprotein (N) gene of these isolates classified all of them as wild type MV of D6 genotype. MVs of D6 genotype with identical nucleotide sequences in the region analyzed were also identified during the 1997 measles epidemic in Brazil and the 1999 measles outbreak in Uruguai. These results suggest that the MVs associated with the 1998 measles epidemic in Argentina might have originated from Brazil. As the D6 genotype is also widely distributed in Europe, it is possible that this genotype was brought to South America from Europe.

[Characterization of isolated adenovirus associated with acute lower respiratory infection in pediatrics]

BACKGROUND

Acute respiratory infection (ARI) are a health care problem as the adenovirus (ADV) has shown to be one of the most frequent viral agents detected in children admitted for mild ARI in the authors medium.

METHODS

Over a 7-year period (1988-1994) ADV isolated from patients under the age of 5, admitted for mild ARI in hospitals in the city of Buenos Aires (Argentina). All the strains were isolated in HEp-2 cell cultures from nasopharyngeal aspirates in which the presence of ADV was detected by indirect immunofluorescence with monoclonal antibodies. Antigenic characterization was performed by sero- and genome neutralization with restriction enzymes.

RESULTS

The isolates corresponded to the genomic variants of ADV 7i, ADV 7c and to a greater number of ADV 7h. An increase was observed in the quantity of cases in the second half of the year. In the population studied, the most commonly infected were males (67.9%) and patients from 2 months to 1 year in age (89.2%). Sixty-six percent of the cases were severe infections with the length of hospitalization being greater than that of patients normally admitted for mild ARI by other virus and showed a high mortality.

CONCLUSIONS

All the above events suggest that the genomic variants detected are highly pathogenic.

[Detection of Chlamydia trachomatis in children with acute lower respiratory infection]

BACKGROUND

Diagnosis of respiratory tract infections due to Chlamydia trachomatis in pediatric patients is very important because of its complications and sequelae. The aim of the present study was to evaluate the performance of rapid methods for reading this diagnosis in 111 children with lower acute respiratory disease.

MATERIAL AND METHODS

Their nasopharyngeal aspirates were studied for detection of Chlamydia spp. antigens using enzyme immunoassay, indirect immunofluorescence and isolation in cell culture. The presence of respiratory viruses was also investigated for immunofluorescence.

RESULTS

Chlamydia spp. were isolated from 16 samples (14.4%) using cell monolayer cultures. They were detected in 22 samples by immunofluorescence (19.8%) and in seven samples by enzyme immunoassay (6.5%). Respiratory viruses were detected in 77 samples (69.4%). Sixty two percent of cell culture positive samples for Chlamydia were also positive for respiratory syncytial virus and 6% were positive for adenovirus. Sensitivity and specificity of immunofluorescence were 37.5% and 83.1% respectively using Chlamydia cell culture as "golden standard". For enzyme immunoassay these percentages were 26 and 96.8% respectively.

CONCLUSIONS

The values obtained are not acceptable for recommending these methods for detecting Chlamydia spp. from nasopharyngeal aspirates. It will be necessary to modify these techniques or to develop alternative methods in order to rapidly and easily obtain a diagnosis of respiratory tract infections due to Chlamydia spp.

[Etiological and clinical evaluation of low acute respiratory infections in children]

Viral laboratory diagnosis was correlated with clinical and epidemiological data from 80 hospitalized children with acute lower respiratory infection (ALRI). They all were less than 5 years-old and were studied from May to September 1993. Fifteen percent of them were malnourished and 75% had some unsatisfied basic necessity. Nasopharingeal aspirates were obtained the first day of hospitalization, and diagnosis for respiratory viruses was performed by the immunofluorescence test with monoclonal antibodies. Routine laboratory determinations, x-ray studies, and clinical data were not conclusive to determine viral etiology. Forty-one percent of the children had a positive viral diagnosis: the most important agent was Respiratory Syncytial Virus (78.7%) followed by Adenovirus (9.1%), Influenza A (6.1%) and Parainfluenza (3%). The peak of incidence was observed in June and the majority of the patients remained hospitalized less than 10 days. Six children died: two of them had viral pneumonia and could not receive mechanical respiratory assistance. The percentage of children who received antibiotics was high, 61.2%, in spite of the fact that 34.7% of these patients had a laboratory confirmed viral etiology. The availability of rapid laboratory viral diagnosis may contribute to decrease the use of antibiotics and improve the management of patients.

Rapid immunoenzymatic technique for titration of rabies antibodies IgG and IgM results

Techniques usually employed for the detection of rabies' antibodies are costly, time consuming, and sometimes fail to detect early antibodies. The introduction of immunoenzymatic techniques in the serology of viral disease represents a new and important advance. We therefore adapted this technique to the detection of rabies antibodies. We have found that the sera from rabies patients who had not received antirabies treatment do not show seroneutralizing antibodies until several days after the onset of symptoms. However, antibodies can be detected some days earlier by the immunoenzymatic method in the same samples. Furthermore, the immunoenzymatic test was applied to the detection of both the IgM or the IgG class of antirabies antibodies using an antihuman Ig-or antihuman IgG-peroxydase conjugate.

[Evaluation of cellular immunity after rabies vaccination in man]

The peripheral lymphocytes of vaccinated men were stimulated by homologous antigen or its subunits (nucleocapsid and glycoprotein) or by some parent viruses (Mokola and Lagos). All subjects produced a high level of antibody. A difference was noted between the two types of immunity. A lack of cell-mediated immunity could explain the very few failures in Pasteur antirabies treatment.

[Glycogen synthase activity in parodontal disease (author's transl)]

A biochemical study of an enzyme participating in the synthesis of glycogen is presented, with particular regard to the fluctuations in the amounts of this polysaccharide in human gingival epithelium, during inflammation. The increase in the activity of UDPglucose : glycogen glucosyltransferase can be related to the accumulation of glycogen. Some kinetic parameters of this enzyme are described.

[Rapid detection of rabies antibodies by immunoenzymatic assay]

The antigen is a semipurified tissue culture virus, and peroxidase conjugated anti-human immunoglobulines are used. When sera from immunized humans are evaluated by this procedure, the values obtained show a good correlation with seroneutralization titres. The detection of antibodies by this method is earlier than by seroneutralization.