Llama Research Articles

Polymorphisms in MC1R and ASIP genes and their association with coat color phenotypes in llamas (Lama glama)

The melanocortin 1-receptor (MC1R) and the agouti signaling protein (ASIP) are the major genes controlling the type and location of pigments produced in mammals. In recent years, polymorphisms in these genes have been associated with coat color variation in a number of species. Llamas (Lama glama) are characterized by a great diversity of coat colors. However, the genetic basis of coat color determination is still unknown. Here, we sequenced the MC1R and ASIP genes in llamas and studied the association between the polymorphisms identified and the coat color. Sequence analysis revealed ten nonsynonymous single nucleotide polymorphisms in the MC1R gene. Three main haplotypes were identified, none of which were completely associated to a particular color phenotype. However, significant association was detected between the MC1R*1 haplotype and the presence of pigmented coat (P<0.0001). Compared to the wild allele, MC1R*1 carried two amino acid substitutions, p.G126S and p.V87M. This last replacement occurs at a highly conserved residue among mammals and the same substitution has been previously associated to melanic phenotypes in avian species. Furthermore, two polymorphisms in ASIP exon 4, a 57bp deletion (c.325_381del) and c.292C>T that are both predicted to have a deleterious effect on the protein, were found in homozygous state or combined in most llamas with eumelanic coat.

Serology and longevity of immunity against Echinococcus granulosus in sheep and llama induced by an oil-based EG95 vaccine.

An oil-based formulation of the EG95 vaccine to protect grazing animals against infection with Echinococcus granulosus was formulated in Argentina. The efficacy of the vaccine was monitored by serology in sheep and llama (Lama glama) and was compared to the serology in sheep previously published using a QuilA-adjuvanted vaccine. Long-term efficacy was also tested in sheep by challenging with E. granulosus eggs of the G1 strain 4 years after the beginning of the trial. The serological results for both sheep and llama were similar to those described previously, except that there was a more rapid response after the first vaccination. A third vaccination given after 1 year resulted in a transient boost in serology that lasted for about 12 months, which was similar to results previously described. Sheep challenged after 4 years with three vaccinations presented 84·2% reduction of live cysts counts compared with control group, and after a fourth vaccination prior to challenge, this reduction was 94·7%. The oil-based vaccine appeared to be bio-equivalent to the QuilA vaccine.

A model for llama (Lama glamaLinnaeus, 1758) domestication in the southern Andes

Fil: Yacobaccio, Hugo Daniel. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina. Universidad de Buenos Aires; Argentina

Prospects for rewilding with camelids

The wild camelids wild Bactrian camel (Camelus ferus), guanaco (Lama guanicoe), and vicuña (Vicugna vicugna) as well as their domestic relatives llama (Lama glama), alpaca (Vicugna pacos), dromedary (Camelus dromedarius) and domestic Bactrian camel (Camelus bactrianus) may be good candidates for rewilding, either as proxy species for extinct camelids or other herbivores, or as reintroductions to their former ranges. Camels were among the first species recommended for Pleistocene rewilding. Camelids have been abundant and widely distributed since the mid-Cenozoic and were among the first species recommended for Pleistocene rewilding. They show a range of adaptations to dry and marginal habitats, and have been found in deserts, grasslands and savannas throughout paleohistory. Camelids have also developed close relationships with pastoralist and farming cultures wherever they occur. We review the evolutionary and paleoecological history of extinct and extant camelids, and then discuss their potential ecological roles within rewilding projects for deserts, grasslands and savannas. The functional ecosystem ecology of camelids has not been well researched, and we highlight functions that camelids are likely to have, but which require further study. We also discuss alternative rewilding-inspired land-use models given the close relationships between humans and some camelid species.

Combining somatic mutations present in different in vivo affinity-matured antibodies isolated from immunized Lama glama yields ultra-potent antibody therapeutics.

Highly potent human antibodies are required to therapeutically neutralize cytokines such as interleukin-6 (IL-6) that is involved in many inflammatory diseases and malignancies. Although a number of mutagenesis approaches exist to perform antibody affinity maturation, these may cause antibody instability and production issues. Thus, a robust and easy antibody affinity maturation strategy to increase antibody potency remains highly desirable. By immunizing llama, cloning the 'immune' antibody repertoire and using phage display, we selected a diverse set of IL-6 antagonistic Fabs. Heavy chain shuffling was performed on the Fab with lowest off-rate, resulting in a panel of variants with even lower off-rate. Structural analysis of the Fab:IL-6 complex suggests that the increased affinity was partly due to a serine to tyrosine switch in HCDR2. This translated into neutralizing capacity in an in vivo model of IL-6 induced SAA production. Finally, a novel Fab library was designed, encoding all variations found in the natural repertoire of VH genes identified after heavy chain shuffling. High stringency selections resulted in identification of a Fab with 250-fold increased potency when re-formatted into IgG1. Compared with a heavily engineered anti-IL-6 monoclonal antibody currently in clinical development, this IgG was at least equally potent, showing the engineering process to have had led to a highly potent anti-IL-6 antibody.

Sarcocystis masoni, n. sp. (Apicomplexa: Sarcocystidae), and redescription of Sarcocystis aucheniae from llama (Lama glama), guanaco (Lama guanicoe) and alpaca (Vicugna pacos).

There is considerable confusion concerning the species of Sarcocystis in South American camelids (SAC). Several species names have been used; however, proper descriptions are lacking. In the present paper, we redescribe the macroscopic sarcocyst forming Sarcocystis aucheniae and describe and propose a new name, Sarcocystis masoni for the microscopic sarcocyst forming species. Muscles samples were obtained from llamas (Lama glama) and guanacos (Lama guanicoe) from Argentina and from alpacas (Vicugna pacos) and llamas from Peru. Individual sarcocysts were processed by optical and electron microscopy, and molecular studies. Microscopic sarcocysts of S. masoni were up to 800 µm long and 35-95 µm wide, the sarcocyst wall was 2·5-3·5 µm thick, and had conical to cylindrical villar protrusions (vp) with several microtubules. Each vp had 11 or more rows of knob-like projections. Seven 18S rRNA gene sequences obtained from sarcocysts revealed 95-96% identity with other Sarcocystis spp. sequences reported in the GenBank. Sarcocysts of S. aucheniae were macroscopic, up to 1·2 cm long and surrounded by a dense and laminar 50 µm thick secondary cyst wall. The sarcocyst wall was up to 10 µm thick, and had branched vp, appearing like cauliflower. Comparison of the 11 sequences obtained from individual macroscopic cysts evidenced a 98-99% of sequence homology with other S. aucheniae sequences. In conclusion, 2 morphologically and molecularly different Sarcocystis species, S. masoni (microscopic cysts) and S. aucheniae (macroscopic cysts), were identified affecting different SAC from Argentina and Peru.

Pharmacokinetics of Immediate and Sustained Release Cephalexin Administered by Different Routes to Llamas (Lama glama).

We investigate the pharmacokinetics of two different cephalexin formulations administered to llamas by the intravenous (IV), intramuscular (IM), and subcutaneous (SC) routes, the minimum inhibitory concentration (MIC) of cephalexin against some Escherichia coli and staphylococci isolated from llamas, and we apply the PK/PD modelling approach, so that effective dosage recommendations for this species could be made. Six llamas received immediate (10 mg/kg, IV, IM, and SC) and sustained (8 mg/kg IM, SC) release cephalexin. Pharmacokinetic parameters were calculated by noncompartmental approach. Immediate release SC administration produced a significantly longer elimination half-life as compared with the IV and IM administration (1.3 ± 0.2 versus 0.6 ± 0.1 and 0.6 ± 0.1 h, resp.) and higher mean absorption time as compared with the IM administration (1.7 ± 0.5 versus 0.6 ± 0.4 h). Absolute bioavailability was in the range of 72–89% for both formulations and routes of administration. Cephalexin MIC90 values against staphylococci and E. coli were 1.0 and 8.0 μg/mL, respectively. Our results show that the immediate release formulation (10 mg/kg) would be effective for treating staphylococcal infections administered every 8 h (IM) or 12 h (SC), whereas the sustained release formulation (8 mg/kg) would require the IM or SC administration every 12 or 24 h, respectively.

Low habitat overlap at landscape scale between wild camelids and feral donkeys in the Chilean desert

Feral domestic ungulates may compete with the populations of wild herbivores with which they coexist, particularly so in arid regions. The potential competition between wild camelids and feral donkeys at the eastern sector of the Atacama Desert is evaluated in terms of their coincidence or segregation in habitat use and complemented with a comparison of reproductive output (yearling/adult ratio) of vicuña family groups in the proximity vs. distant from donkey observations. Habitat use of wild camelids and donkeys was sampled driving some 1250 km of roads and tracks at the dry and wet seasons. There were 221 vicuñas (Vicugna vicugna) sightings, 77 for donkeys (Equus asinus), 25 for guanacos (Lama guanicoe) and 8 for hybrids between guanacos and domestic llamas (Lama glama), as well as 174 randomly selected control locations. By means of Generalised Discriminant Analysis and Analysis of Variance we show that all ungulates actively select their habitat, with significant differences between use and availability in the area. Donkeys are relatively abundant in comparison with camelids and coincide broadly with both of them across the altitudinal gradient, but they fall between them in local scale habitat selection and do not seem to force their displacement from their preferred habitats. Thus donkeys occur preferentially on slopes with a high cover of tall shrubs, whereas vicuñas use valley bottoms with grass and guanacos the upper slope zones with grass. The potential for competition between donkeys and wild camelids is thus limited and it does not affect the reproductive output of vicuña in this region. Therefore, with the present knowledge we suggest that population control is not currently merited for feral donkeys.

Gross, mineral and fatty acid composition of alpaca (Vicugna pacos) milk at 30 and 60 days of lactation

The aim of this study was to investigate the composition of alpaca milk in order to improve knowledge of the nutritional needs of crias during their first months of life. Analyses of alpaca milk were performed in terms of chemical, mineral composition and fatty acid profile during the first two months of lactation. Percentages of fat, protein, casein and ash did not change in the first two months of lactation. Alpaca milk showed a similar protein content to sheep and camelid milk such as llama (Lama glama), lower casein content compared to ruminants, and similar fat percentages to cow and goat milk. The Ca and P content was similar to cow milk. Concerning the fatty acid profile, alpaca milk had higher conjugated linoleic acid (C18:2 cis 9, trans 11) and unsaturated fatty acid contents than ruminant milk, and a low percentage of fatty acids with chains <C14: 0. In fact, during the first months of life, alpaca offspring may not sufficiently exploit these fatty acids. Ruminant milk cannot be considered as an ideal surrogate for the nutritional needs of crias.

Birth of live llama (Lama glama) derived from embryo transfer storage at 5 °C for 24 h

The objective of the present work was to evaluate the efficacy of maintaining llama embryos metabolically inhibited but viable at 5°C during 24h. Adult females (n=20) were used as embryo donors and were superstimulated with eCG. A total 61 embryos were non-surgically collected from 16 of the 20 llamas flushed at Day 7 after mating. Fourteen excellent hatched blastocysts were stored in sterile test tubes containing 1.5ml of TCM 199-Hepes+10% cow serum (v/v concentration)+antibiotics and cooled to 5°C (cooling rate=0.5°C/min) and maintained at 5°C during 24h. After this, the embryos were warmed on warming plate (38°C), washed three times and loaded individually into 0.25ml French straws. Fourteen adult llamas were used as recipients and embryos were transferred only into the left uterine horn of the recipient regardless of side ovulation. All recipient llamas were pregnancy tested by transrectal ultrasonography at 45 days after transfer. Three (21.5%) pregnant females were detected and delivered three normal healthy male calves at term. To our knowledge, these offspring are the first llamas produced following transfer of refrigerated embryos. In summary, llama embryos can be cooled to 5°C and maintained in storage for up to 24h without significant losses of viability.

Oestrogen and Progesterone Receptors and COX‐2 Expression in Endometrial Biopsy Samples During Maternal Recognition of Pregnancy in Llamas (Lama glama)

Endometrial expression of oestrogen receptor-α (ERα), progesterone receptor (PR) and cyclooxigenase-2 (COX-2) was evaluated in non-pregnant and pregnant llamas during the period when luteolysis/maternal recognition of pregnancy is expected to occur. Females (n = 28) were divided into two groups: non-pregnant llamas were induced to ovulate with a Buserelin injection, and endometrial biopsies were obtained on day 8 (n = 5) or 12 (n = 5) post-induction of ovulation. Animals of the pregnant group (n = 18) were mated with a fertile male. Pregnancy was confirmed by the visualization of the embryo collected by transcervical flushing in 5 of 9 animals on day 8 post-mating and by progesterone profile on day 12 post-mating in 4 of 9 animals, when endometrial biopsies were obtained. An immunohistochemical technique was used to evaluate receptors population and COX-2 expression. Pregnant llamas showed a higher percentage of positive cells and stronger intensity for ERα than for non-pregnant llamas in stroma on day 8 and in the luminal epithelium on day 12 post-induction of ovulation, while a deep decrease in endometrial PR population was reported in pregnant llamas on that day in luminal and glandular epithelia and stroma. In the luminal epithelium, COX-2 expression was lower in pregnant than in non-pregnant animals. Briefly, the increase of ERα in pregnant llamas gives further support to the hypothesis that oestrogens are involved in the mechanism of maternal recognition of pregnancy. Endometrial PR decrease in pregnant llamas might be a necessary event to allow the expression of proteins involved in conceptus attachment, a mechanism widely accepted in other species. Moreover, embryo seems to attenuate maternal PGF(2α) secretion during early pregnancy by decreasing the endometrial expression of COX-2 in the luminal epithelium of pregnant llamas.

Llama (Lama glama) semen collection via thermo-electric artificial vagina: Effect of seasonality and collection interval on ejaculate characteristics

Adult male Llamas (Lama glama) (n=6) were collected using a receptive female and a thermo-electric artificial vagina assembled with a polyethylene collection bag with the following objectives: (a) to develop a reliable and repeatable semen collection technique for Llama, (b) validate semen evaluation tests for Llama, and (c) to determine the effect of collection frequency and season on Llama semen characteristics. First, the semen and sperm variables were recorded and validated through their own repeatability. Semen collection intervals tested were: 1X/week for three weeks and 3X/week for another three weeks, the second collection period occurring after two weeks of sexual rest. The collection frequency of 3X/week significantly reduced (P<0.05) the sperm viability, motility, concentration, Total Sperm/Ejaculate, Total Motile Sperm/Ejaculate and Total Live Sperm/Ejaculate, but improved Total Sperm/Week and Total Live Sperm/Week. All recorded variables were significantly higher during the summer in comparison to the spring with the exception of morphology abnormalities, volume, and viability. Also, the 1X/week versus the 3X/week semen collection frequencies did not produce a significant difference in the percent of total motile sperm/week. Based on semen and sperm characteristics evaluated herein, Llama semen collected in the summer was better (P<0.05), with regard to the majority of the variables analyzed, than semen collected in the spring.

Short Communication. Embryo yield in llamas synchronized with two different intravaginal progesterone-releasing devices and superovulated with eCG

The objectives of this study were to compare the effects of two intravaginal devices (ID) containing the same dose (0.5 g) of progesterone (P4) on subsequent ovarian response, embryo production and circulating P4 concentration profile in llamas (Lama glama) treated with equine chorionic gonadotropin (eCG) for ovarian superstimulation. Female llamas were randomly assigned (n = 10 llamas per group) to one of the following groups and treated (Day 0) with an ID containing 0.5 g of vegetal P4 to synchronize the emergence of a new follicular wave: i) DIB 0.5® and ii) Cronipres M15®. On Day 3 llamas were intramuscularly treated with 1000 IU of eCG. The IDs were removed on Day 7. Llamas were naturally mated (Day 9) and treated with GnRH analogue to induce ovulation. A second mating was allowed 24 h later. Embryos were collected between 7 and 8 days after the first mating. Blood samples were taken every day from Day 0 to Day 7 to measure circulating P4 concentrations. The results indicated that DIB device maintained greater plasma P4 levels as compared to Cronipres until Day 2. However, the mean (± SD) number of corpora lutea and recovered embryos was not affected (p &lt; 0.05) by the type of ID (5.3 ± 2.6 vs 4.2 ± 2.2 and 3.5 ± 2.7 vs 2.6 ± 3.0 for DIB and Cronipres, respectively). In conclusion, both DIB and Cronipres devices can be successfully used to synchronize the emergence of follicular wave prior to a single dose of eCG in superovulation protocol in llamas.

Camelid heavy chain only antibody fragment domain against β-site of amyloid precursor protein cleaving enzyme 1 inhibits β-secretase activity in vitro and in vivo.

Accumulation and aggregation of the amyloid-β (Aβ) peptide is associated with Alzheimer's disease (AD). Aβ is generated from the amyloid precursor protein by the successive action of two membrane-associated processing enzymes: β-secretase or β-site of amyloid precursor protein cleaving enzyme 1 (BACE1) and γ-secretase. Inhibition of one or both of these enzymes prevents Aβ generation and the accompanying Aβ accumulation. Antigen binding fragments from camelid heavy chain only antibodies (VHHs) were found to exert excellent enzyme inhibition activity. In the present study, we generated VHHs against BACE1 by active immunization of Lama glama with the recombinant BACE1 protein. Two classes of VHHs were selected from a VHH-phage display library by competitive elution with a peptide encoding the Swedish mutation variant of the BACE1 processing site. One VHH was found to inhibit the enzyme activity of BACE1 in vitro and in cell culture, whereas two other VHHs were found to stimulate BACE1 activity under the same conditions in vitro. Furthermore, an in vivo study with a transgenic AD mouse model, using intracisternal injection of the inhibitory VHH, led to acute reduction of the Aβ load in the blood and brain. This inhibitory VHH may be considered as a candidate molecule for a therapy directed towards reduction of Aβ load and prevention of AD progression. Both the inhibitory and stimulatory VHH may be useful for improving our understanding of the structure-function relationship of BACE1, as well as its role in AD progression. The GenBank sequence accession numbers are KR363186 for VHH B1a; KR363187 for VHH B3a; and KR363188 for VHH B5a.

Detection of Salmonella spp. from some wild captive herbivores in Iran and determination of serogroup, antibiotic susceptibility and presence of invA gene in the isolated strains

Salmonella spp. are zoonotic enteric bacteria able to infect humans, livestock and wildlife. The aim of this study was to investigate the prevalence of Salmonella (spp.) and to determine antibiotic susceptibility, serogrouping and presence of invA gene ( Salmonella Invasion Gene A) in the detected strains in wild captive herbivores in Iran. The fecal samples of 103 animals from 8 different species were evaluated for presence of the Salmonella . Results indicated that 9.7% of animals were positive for Salmonella , all of these strains belonged to D serogroup, also all the Salmonella strains harbored invA gene. In vitro antibiotic activities of 10 antibiotic substances against the isolates were determined by disc diffusion test. The highest rate of resistance was against Amoxicillin (100%), Tetracycline (80%), Neomycin (60%), Lincospectin (50%) and Enrofloxacin (40%), Resistance to Furazolidone wasn't observed. In conclusion, these species can act as a reservoir for Salmonella . Also, since the study was conducted in some parts of Iran, a more accurate conclusion needs more distributed sampling. To our knowledge this is the first study which reports the fecal shedding of Salmonella from Cervus elaphus , Capra aegarus , Oryx leucoryx , Ammotragus lervia and Lama glama in Iran.

Evaluation of the acrosomal status in Lama glama sperm incubated with acrosome reaction inducers

The objectives of this study were to evaluate the effect of different acrosome reaction (AR) inducers on viability and acrosomal status in llama spermatozoa, by using the FITC-PNA/PI technique and evaluate if there is a positive correlation between the FITC-PNA/PI and the Coomassie blue (CB) staining techniques. After incubating twenty ejaculates in 0.1% collagenase the centrifuged pellets were resuspended in TALP–BSA medium. An aliquot was sonicated to remove the acrosomal content (positive control). The rest of the sample was incubated for 3h at 38°C with 5% CO2 and 100% humidity. TreatmentsThree aliquots were further incubated 1h with one of the following AR inducers: calcium ionophore, ionomycin or progesterone. ControlsOne without inducers and the other, incubated with dimethyl sulfoxide (vehicle of the inducing agents). Acrosomes were evaluated at time 0 and after 4h incubation. Calcium ionophore was the most potent agent for inducing the AR (67.2±14.4% live+dead AR sperm) (P<0.05). These samples showed no motility and viability was very low (0–30%). Both ionomycin and progesterone presented significantly higher (P<0.05) percentages of total AR sperm than the controls, but had similar percentages of dead reacted sperm to the controls. A positive correlation was observed between the intact acrosome FITC-PNA/PI pattern (live+dead sperm) and the acrosome-present CB pattern (r=0.64; P=0.000) in all the evaluated samples. Conclusionsthe FITC-PNA/PI technique simultaneously evaluates viability and acrosomal status in llama spermatozoa and calcium ionophore could be used as a control of AR.

Anaplasma infection of Bactrian camels (Camelus bactrianus) and ticks in Xinjiang, China.

BackgroundTo date, anaplasmosis has been reported to be a subclinical disease in Indian and Arabian one-humped camels (Camelus dromedarius) and llamas (Lama glama). However, no information on Anaplasma infection in two-humped Bactrian camels (Camelus bactrianus) in China has been published to date. The aim of this study was to investigate the prevalence of Anaplasma spp. in domestic Bactrian camels and ticks in Xinjiang, China.FindingsA total of 382 ticks were collected from the Bactrian camels and from environmental sources. Of these, 84 were morphologically identified as belonging to the Rhipicephalus sanguineus group and genetically identified (12S rDNA, 16S rDNA and the cytochrome c oxidase 1 genes) as R. sanguineus group ticks (temporally designated as Rhipicephalus sp. Xinjiang). PCR testing showed that 7.2 % (20/279) of the camels harbored Anaplasma platys DNA. However, microscopic examination revealed no A. platys inclusions in blood smears from the camels. The PCR prevalence of A. platys DNA was 9.5 % (6/63) in Rhipicephalus sp. Xinjiang from the Bactrian camels and 14.3 % (3/21) in Rhipicephalus sp. Xinjiang from the vegetation. A. platys DNA was not detected by PCR in other tick species (Hyalomma asiaticum, Dermacentor niveus and Hyalomma dromedarii), and no other Anaplasma species were detected in these samples.ConclusionsThis is the first report of A. platys in Bactrian camels in Xinjiang, China. The moderate positivity observed indicates that these animals might be a natural host for this pathogen in China.

Fibre quality of South American camelids in Argentina: a review

SummaryArgentina's annual camelid fibre production is estimated at 60 000 kg for llama (Lama glama), somewhat more than 2 000 kg for guanaco (Lama guanicoe) and about 845 kg for vicuña (Vicugna vicugna). The potential for increasing these amounts is huge considering that barely 30 percent of llamas are shorn and considering the size of the wild camelid population in the country. A compilation of published and unpublished work confirms that almost 50 percent of the llamas are single-coated, about 40 percent have white fleeces and that average fibre diameter is about 22 µm in the main llama production area. In general, there is a wide variation in fleece weights and fibre quality between and within herds. However, a llama fleece classing and pricing system is not yet in place to motivate implementation of breeding programmes. Guanaco and vicuña fleeces are double-coated but the fine undercoat represents more than 80 percent of the fleece weight. The proportion of down fibre remaining after mechanical dehairing is only 50 percent in guanacos and 70 percent in vicuñas. The guanaco undercoat fibre diameter is about 16 µm and vicuña fibre diameter is typically between 13 and 14 µm. Both fibres are relatively short. Research is needed to establish optimum shearing season and shearing frequency that results in fibre quality demanded for handcraft and industry in each of the three species.

Camelid Ig V genes reveal significant human homology not seen in therapeutic target genes, providing for a powerful therapeutic antibody platform

Camelid immunoglobulin variable (IGV) regions were found homologous to their human counterparts; however, the germline V repertoires of camelid heavy and light chains are still incomplete and their therapeutic potential is only beginning to be appreciated. We therefore leveraged the publicly available HTG and WGS databases of Lama pacos and Camelus ferus to retrieve the germline repertoire of V genes using human IGV genes as reference. In addition, we amplified IGKV and IGLV genes to uncover the V germline repertoire of Lama glama and sequenced BAC clones covering part of the Lama pacos IGK and IGL loci. Our in silico analysis showed that camelid counterparts of all human IGKV and IGLV families and most IGHV families could be identified, based on canonical structure and sequence homology. Interestingly, this sequence homology seemed largely restricted to the Ig V genes and was far less apparent in other genes: 6 therapeutically relevant target genes differed significantly from their human orthologs. This contributed to efficient immunization of llamas with the human proteins CD70, MET, interleukin (IL)-1β and IL-6, resulting in large panels of functional antibodies. The in silico predicted human-homologous canonical folds of camelid-derived antibodies were confirmed by X-ray crystallography solving the structure of 2 selected camelid anti-CD70 and anti-MET antibodies. These antibodies showed identical fold combinations as found in the corresponding human germline V families, yielding binding site structures closely similar to those occurring in human antibodies. In conclusion, our results indicate that active immunization of camelids can be a powerful therapeutic antibody platform.

Molecular Characterization of the Llamas (Lama glama) Casein Cluster Genes Transcripts (CSN1S1, CSN2, CSN1S2, CSN3) and Regulatory Regions.

In the present paper, we report for the first time the characterization of llama (Lama glama) caseins at transcriptomic and genetic level. A total of 288 casein clones transcripts were analysed from two lactating llamas. The most represented mRNA populations were those correctly assembled (85.07%) and they encoded for mature proteins of 215, 217, 187 and 162 amino acids respectively for the CSN1S1, CSN2, CSN1S2 and CSN3 genes. The exonic subdivision evidenced a structure made of 21, 9, 17 and 6 exons for the αs1-, β-, αs2- and κ-casein genes respectively. Exon skipping and duplication events were evidenced. Two variants A and B were identified in the αs1-casein gene as result of the alternative out-splicing of the exon 18. An additional exon coding for a novel esapeptide was found to be cryptic in the κ-casein gene, whereas one extra exon was found in the αs2-casein gene by the comparison with the Camelus dromedaries sequence. A total of 28 putative phosphorylated motifs highlighted a complex heterogeneity and a potential variable degree of post-translational modifications. Ninety-six polymorphic sites were found through the comparison of the lama casein cDNAs with the homologous camel sequences, whereas the first description and characterization of the 5’- and 3’-regulatory regions allowed to identify the main putative consensus sequences involved in the casein genes expression, thus opening the way to new investigations -so far- never achieved in this species.