Nasopharyngeal pneumococcal carriage of children attending day care centers in Korea: comparison between children immunized with 7-valent pneumococcal conjugate vaccine and non-immunized

To confirm the effect of 7-valent pneumococcal conjugate vaccine (PCV7), pneumococcal nasopharyngeal (NP) carriage was compared between vaccinated (3 + 1 doses PCV7) and non-vaccinated children. Vaccinated subjects were recruited from highly vaccinated regions (≥ 60%), Seoul and Incheon whereas control subjects were recruited from Jeju Island where vaccination rates are low (< 15%). NP swabs were obtained from 400 children aged 18-59 months. Serotype and antibiotic susceptibility was analyzed. Pneumococcal carriage rate was 18.0% (36/200) and 31.5% (63/200) for the vaccinated and control group, respectively. Among those vaccinated, 41.7% (15/36) of the serotypes were vaccine-related type (VRT: 6A, 6C, 19A) with the most common serotype 6C. The next common type was non-typable/non-capsule 30.6% (11/36) followed by non-vaccine type 16.7% (6/36) and vaccine type (VT) serotypes were found in only 11.1% (4/36). In contrast, 52.4% (33/63) of the isolates in the control group were VT. Resistance rates for penicillin and erythromycin were lower in the vaccine group (vaccine vs control; penicillin 45.2% vs 71.4%, erythromycin 74.2% vs 90.5%, P < 0.05). Multi-drug resistance was also lower in vaccinated subjects (vaccine vs control; 45.2% vs 69.8%, P < 0.05). PCV7 reduces carriage in VT which leads to replacement of pneumococci by antibiotic susceptible VRT or non-vaccine type strains.     

Changing epidemiology of invasive pneumococcal disease following increased coverage with the heptavalent conjugate vaccine in Navarre, Spain

The present study evaluated changes in the incidence of invasive pneumococcal disease (IPD) and the pattern of serotypes isolated in Navarre, Spain, after the introduction and increased coverage of the heptavalent pneumococcal conjugate vaccine (PCV7). All cases with isolation of pneumococcus from normally sterile bodily fluids were included. The incidence of IPD in children and adults was compared for the periods 2001–2002 and 2006–2007. By the end of 2002, only 11% of children aged <5 years had received any dose of PCV7, whereas, beginning in 2007, the proportion exceeded 50%. Among the cases of IPD aged <5 years, the percentage of those vaccinated increased from 7% during 2001–2002 to 53% during 2006–2007 (p <0.001). The incidence of IPD from PCV7-serotypes decreased by 85% in children <5 years (p <0.001), by 45% in the population aged 5–64 years (p 0.10) and by 68% in those ≥65 years (p 0.004). By contrast, the incidence of IPD from non-PCV7 serotypes increased by 40% overall (p 0.006). The incidence of IPD from all serotypes did not change significantly in children <5 years (from 83 to 72 per 100 000) or in the total population (from 15.8 to 16.3 per 100 000). The percentage of cases as a result of serotypes 7 and 19A increased significantly in both children and adults. No significant changes were seen in the clinical forms of IPD. The pattern of serotypes causing IPD has changed, in both children and adults, following the increased coverage of PCV7, although the incidence has been reduced only slightly.     

Caseinolytic protease: a protein vaccine which could elicit serotype‐independent protection against invasive pneumococcal infection

Invasive pneumococcal diseases incur significant mortality, morbidity and economic costs. The most effective strategy currently available to reduce the burden of these diseases is vaccination. In this study, we evaluated the protective efficacy of immunizing mice with caseinolytic protease (ClpP) protein antigen whose gene sequences were shown to be highly conserved in different strains of Streptococcus pneumoniae in an invasive‐disease model (intraperitoneal infection model), and protection against invasive challenge with 12 different serotypes of S. pneumoniae was assessed in two murine strains. Our findings demonstrated that active immunization with ClpP and passive immunization with antibodies specific for ClpP could elicit serotype‐independent protection effectively against invasive pneumococcal infection. Therefore, to our knowledge, this study is the first report that immunization with single pneumococcal ClpP protein antigen could protect against such broad‐range pneumococal strains, which thus supports the development of ClpP as a human penumococcal vaccine.     

Comparison of the pulmonary response against lethal and non-lethal intranasal challenges with two different pneumococcal strains

The differences between the immune response elicited during a self-limiting and a life-threatening lung infection with Streptococcus pneumoniae was analyzed in a mouse model of intranasal challenge using two different pneumococcal strains. M10, a serotype 11A strain, induced an early response within the first 12 h after the challenge, which was characterized by the early local secretion of TNF-α and IL-6, followed by a sharp and rapid neutrophil influx. Bacterial loads in the lungs already started to fall at 12 h after the challenge and no pneumococci could be recovered after 36 h, at the time point when the animals started to show improvement in disease symptoms. ATCC6303, a serotype 3 strain, on the other hand, showed only a late increase in local TNF-α and IL-6 levels, when bacterial growth already seems to be out of control. Although cell influx was also observed, neutrophil rise was not as marked as with M10 (type 11A). Pneumococcal loads increased constantly and bacteria started to be recovered from the blood at 30 h after the challenge. After this time point, animals showed worsening of symptoms and became lethargic. The resolution of the acute infection could be thus correlated with the early induction of proinflammatory cytokines, which could be due to the presence of a thinner polysaccharide capsule in M10 (type 11A), rendering bacterial components capable of activating the innate immune response more accessible.     

E-cadherin is a receptor for the common protein pneumococcal surface adhesin A (PsaA) of Streptococcus pneumoniae

Streptococcus pneumoniae (Pnc) binds to nasopharyngeal (NP) epithelial cells in the first steps of nasopharyngeal carriage and colonization through bacterial adhesins. The pneumococcal surface adhesin A (PsaA) has previously been reported to play a significant role in pneumococcal adherence and colonization. Identification of a receptor for PsaA on human epithelium will aid in understanding the pathogenesis of this bacterium. Using recombinant PsaA covalently bound to fluorescent spheres (fluospheres), we show PsaA binds to NP cells through interaction with the human cellular receptor, E-cadherin. SDS-PAGE silver stain analysis demonstrates binding of PsaA to E-cadherin. Recombinant human E-cadherin binds to and blocks PsaA-coated fluospheres and whole transparent bacteria from adhering to NP cells, but does not block a Pnc PsaA(-) mutant. Recombinant E-selectin and human alpha(5)beta(1) integrin did not bind to or block PsaA-coated fluosphere adherence to NP cells. Likewise, if NP cells were preincubated with anti-E-cadherin antibody, there was a significant decrease (46%, P=0.05) in PsaA-coated fluosphere adherence to the cells. Additionally, when using E-cadherin transfected cells, we observed PsaA-coated fluospheres bind more efficiently to cells which express E-cadherin. This work identifies E-cadherin as a receptor on human epithelial cells for the pneumococcal surface adhesin, PsaA.     

Changes in serotype distribution and antibiotic resistance of nasopharyngeal isolates of Streptococcus pneumoniae from children in Korea, after optional use of the 7-valent conjugate vaccine

We investigated serotype distribution and antimicrobial resistance of pneumococcal carriage isolates from children after optional immunization with the 7-valent pneumococcal conjugate vaccine (PCV7) in Korea. From June 2009 to June 2010, 205 (16.5%) pneumococcal isolates were obtained from 1,243 nasopharyngeal aspirates of infants and children at Seoul National University Children's Hospital, Korea. Serotype was determined by Quellung reaction and antibiotic susceptibility was tested by E-test. The results were compared to previous studies done in the pre-PCV7 period. In this study, the most common serotypes were 6A (15.3%), 19A (14.7%), 19F (10.2%), 35B (7.3%), and 6D (5.6%). The proportion of PCV7 serotypes decreased from 61.9% to 23.8% (P < 0.001). The overall penicillin nonsusceptibility rate increased from 83.5% to 95.4% (P = 0.001). This study demonstrates the impact of optional PCV7 vaccination in Korea; the proportion of all PCV7 serotypes except 19F decreased while antimicrobial resistant serotypes 6A and 19A further increased.     

Protection against nasal colonization with Streptococcus pneumoniae by parenteral immunization with a DNA vaccine encoding PspA (Pneumococcal surface protein A)

Pneumococcal surface protein A (PspA) is an important candidate for a cost-effective vaccine with broad coverage against Streptococcus pneumoniae. We have previously shown that intramuscular immunization with PspA as a DNA vaccine induces an immune response characterized by the induction of a balanced IgG1/IgG2a antibody response in BALB/c mice, which was able to efficiently mediate complement deposition onto intact bacteria and to induce protection against an intraperitoneal challenge. We now confirm the results in C57BL/6 mice and further show that the response induced by the DNA vaccine expressing PspA is able to mediate protection against colonization of the nasopharyngeal mucosa even though immunization was given parenterally. Moreover, a positive correlation was observed between IgG1 and the numbers of CFU recovered, whereas an inverse correlation was observed between nasal CFU levels and IgG2a. A positive correlation was also found for IgG1/IgG2a antibody ratios with CFU recovered from the nasopharynx. Therefore, reduction of nasal colonization was strongly associated with increased levels of serum IgG2a complement fixing antibody and low levels of IgG1 antibody which has much less complement fixing activity. Passive transfer of serum from animals immunized with the DNA vaccine expressing PspA was also able to reduce the fraction of mice with high density of colonization of the nasopharynx. Secretion of IFN-γ, but not IL-17, was observed in splenocytes from mice immunized with the DNA vaccine.     

Regional differences in serotype distribution,pneumococcal vaccine coverage,and antimicrobial resistance of invasive pneumococcal disease among German federal states

Continuous nationwide surveillance of invasive pneumococcal disease has been conducted in Germany for more than 15 years. In this study, 3724 isolates were included. A total of 2065 isolates were obtained from children under 16 years of age from 1997 to 2006, and 1659 isolates were obtained from adults aged 16 years and older between 2002 and 2006. Results were classified to federal states, and supra-regional trends were illustrated by classifying the federal states into the regions ‘North-West’, ‘North-East’ and ‘South’. Among childhood isolates, the most common serotypes were 14 (26.4%), 6B (7.7%), 23F (7.4%), 19F (7.1%), 1 (7.0%), 18C (6.2%), and 7F (5.6%). Serotype coverage for the 7-valent conjugate vaccine was 62.3%. For the 10-valent and 13-valent vaccines (both in development) the coverage was 75.5% and 84.8%, respectively. The 23-valent polysaccharide vaccine had a coverage of 87.3%. The coverage varies considerably among the federal states. Penicillin G resistance was observed in 7.4% of meningitis cases. In the non-meningitis group, no intermediate resistant or resistant strains were detected. Among adults, the most common serotypes were 14 (16.9%), 3 (9.2%), 4 (7.8%), 7F (7.5%), 1 (6.8%), and 9V (6.1%). Serotype coverage for the 7-valent conjugate vaccine was 46.5%. For the pneumococcal conjugate vaccines in development, the coverage was 61.1% (10-valent) and 76.3% (13-valent). The 23-valent polysaccharide vaccine had a coverage of 88.7%. Penicillin G resistance was observed in 6.4% of meningitis cases. Among these, considerably higher rates of resistance were observed in the North-East region (13.0%) than in the North-West (7.1%) and South (1.8%) regions.     

双蛋白载体A、C群脑膜炎球菌多糖结合物的免疫效果观察

目的 比较和评价在A、C群脑膜炎球菌多糖结合物中应用两种蛋白作为载体的免疫效果.方法 构建不耐热肠毒素B亚单位(LTB)的克隆载体和表达载体.确定rLTB主要为可溶性表达.应用一步阳离子交换层析对rLTB进行纯化,获得较纯的目的蛋白.利用GM1-ELISA和非变性SDS-PAGE的方法确定纯化后的rLTB能够形成具有生物学活性的五聚体.最后利用化学方法(ADH方法)将通过基因工程手段获得的重组LTB五聚体蛋白与C群脑膜炎球菌多糖(GCMP)耦联,获得多糖蛋白结合物GCMP-rLTB.以单一蛋白破伤风类毒素(TT)为载体的A+C群脑膜炎球菌多糖蛋白结合物(GAMP-TT和GCMP-TT)及同时应用两种蛋白载体的A+C群脑膜炎球菌多糖蛋白结合物(GAMP-TT和GCMP-rLTB)分别通过腹腔注射途径免疫小鼠.应用ELISA方法分别检测小鼠血清中IgG水平.结果 单独以TT为载体的A+C群脑膜炎球菌多糖蛋白结合物(GAMP-TT和GC-MP-TT)和同时以两种蛋白作为载体的A+C群脑膜炎球菌多糖蛋白结合物(GAMP-TT和GCMP-rLTB)通过注射途径免疫小鼠,后者产生的血清多糖特异性IgG水平显著高于前者.结论 双蛋白载体在改善A、C群脑膜炎球菌多糖结合物疫苗的免疫原性方面具有明显优势.

Abstract：

Objective To evaluate the immunogenicity of group A and C meningococcal polysaccharides conjugates using different proteins as carriers. Methods Heat-labile enterotoxin B subunit (LTB)pentamer form was expressed in E. coli. The target protein was identified and purified by cation-exchange chromatography. Then biological activity of rLTB was tested using GM1-ELISA. GCMP was conjugated to rLTB with the chemical method (ADH). Furthermore, the mice were immunized with GAMp-TT/GCMP-TT conjugates and GAMP-TT/GCMP-rLTB conjugates via peritoneal. Finally the anti-polysaccharide antibody was detected. Results The GAMP-TT/GCMP-rLTB conjugate elicits remarkably higher serum antibodies in mice than GAMP-TT/GCMP-TT conjugate. Conclusion These results indicated that polysaccharide conjugates using different proteins as carriers were superior to those using only one protein as carrier.     

Exposure of Thomsen-Friedenreich antigen in Streptococcus pneumoniae infection is dependent on pneumococcal neuraminidase A

Pneumococcal hemolytic uremic syndrome is recognized in a small portion of otherwise healthy children who have or have recently had Streptococcus pneumoniae infections, including severe pneumonia, meningitis, and bacteremia. As in other types of hemolytic uremic syndrome (HUS), pneumococcal HUS is characterized by microangiopathic hemolytic anemia, and thrombocytopenia, usually with extensive kidney damage. Although not demonstrated in vivo, the pathogenesis of pneumococcal HUS has been attributed to the action pneumococcal neuraminidase exposing the usually cryptic Thomsen-Friedenreich antigen (T-antigen) on red blood cells (RBC), and kidney glomeruli. We evaluated the effect of pneumococcal infection on desialylation of RBC and glomeruli during pneumococcal infections in mice. Following intravenous infection with capsular type 19F pneumococci, CFU levels exceeding 1000 CFU/mL blood by the third day were significantly more likely to result in exposed T-antigen on RBC than lower levels of bacteremia. In a pneumonia model, significantly more T-antigen was exposed on RBC in mice treated with penicillin than in those receiving mock treatment. Utilizing mutant pneumococci, we demonstrated that neuraminidase A but not neuraminidase B was necessary for exposure of T-antigen on RBC in vivo. Thus, pneumococcal neuraminidase A is necessary for the exposure of T-antigen in vivo and treatment with penicillin increases this effect. Interestingly, NanA(-) pneumococci were found in the blood in higher numbers and caused more deaths than wild type, NanB(-), or the NanA(-)/NanB(-) pneumococci.     

Vaccine-induced human antibodies to PspA augment complement C3 deposition on Streptococcus pneumoniae

Pneumococcal surface protein (PspA) is a virulence factor expressed by all clinical isolates of Streptococcus pneumoniae. PspAs are variable in structure and have been grouped into clades and cross-reacting families based on sequence similarities and immunologic cross-reactivity. At least 98% of PspAs are found in PspA families 1 or 2. PspA has been shown to interfere with complement deposition on pneumococci, thus reducing opsonization and clearance of bacteria by the host immune system. Prior studies using pooled human sera have shown that PspA interferes with C3 deposition on a single strain of S. pneumoniae, WU2, and that mouse antibody to PspA can enhance the deposition of C3 on WU2. The present studies have demonstrated that these previous findings are representative of most normal human sera and each of seven different strains of S. pneumoniae. It was observed that PspAs of PspA families 1 and 2 could inhibit C3 deposition in the presence of immunoglobulin present in all but 3 of 22 normal human sera. These studies have also demonstrated that rabbit and human antibody to PspA can enhance the deposition of C3 on pneumococci expressing either family 1 or 2 PspAs and either capsular types 2, 3, or 11. A vaccine candidate that can elicit immunity that neutralizes or compensates for S. pneumoniae's ability to thwart host immunity would be of value.     

Analysis of a surface protein of Streptococcus pneumoniae recognised by protective monoclonal antibodies

Using two monoclonal antibodies which protect mice from a fatal challenge with S. pneumoniae, we have identified a surface protein antigen on the pneumococcus. These antibodies recognised components of 84 and 76 kD in a cell wall extract of the nonencapsulated strain, R36A, against which they were made. Absorption experiments indicated that both of the antibodies recognised the same two proteins. The proteins detected by the antibodies in the encapsulated type 2 strain D39 and type 3 strain WU2, exhibited different molecular weights than those proteins detected from R36A. Using a colony blot procedure and a quantitative ELISA, we have shown that these antibodies react with 6 of the 21 pneumococcal strains tested. There was no association between reactivity with these anti-protein antibodies and the capsular serotype of the pneumococcal isolates tested.     

A functional epitope of the pneumococcal surface adhesin A activates nasopharyngeal cells and increases bacterial internalization

Pneumococcal surface adhesin A (PsaA) is a putative pneumococcal (Pnc) adhesin known to bind to nasopharyngeal (NP) epithelial cells. This study evaluated the effect of peptides within a functional domain of PsaA on NP cells. Detroit 562 NP cells were treated with synthetic peptides derived from PsaA (P4, P6, and P7; 28, 12, and 16 amino acids, respectively). The P4 peptide also binds to NP cells. Analysis of P4-treated NP cells by transmission electron microscopy revealed major cytological changes. Of 9 cytokines analyzed, a 6-fold increase in FGFb secretion at 3 and 6h (11-fold at 12h) was found post-P4 treatment of NP cells. There was a simultaneous reduction in the secreted levels of IL-6, IL-8, and VEGF. We observed enhancement in the adherence of Pnc strains to P4-treated NP cells (2-38-fold increase). Enhancement in adherence (2-fold increase) to P4-treated NP cells was also recorded with other streptococcal species (Streptococcus mitis and Streptococcus pyogenes). Internalization experiments demonstrated that 45% of the adherent bacteria were actually internalized after pretreatment with P4 peptide as compared to controls. Peptide fragments of P4, P6 and P7 did not activate NP cells to the extent of P4 peptide. The P4-mediated enhancement of Pnc adherence was blocked (100%) by anti-P4 antibodies, confirming the specificity of the P4 sequence for NP cell activation. Our data suggests that this functional domain of PsaA contained within the P4 sequence binds and activates NP cells to facilitate Pnc invasion.     

Adjuvant modulation of the immune response of mice against the LcrE protein of Chlamydophila pneumoniae

LcrE protein is a TTSS component of Chlamydophila pneumoniae. The immunogenicity and protective effect of recombinant LcrE protein combined either with Freund's or Alum adjuvant were investigated in mice. The immunization with both protocols resulted in a significant reduction of the number of viable C. pneumoniae in the lungs after challenge. Lower IgG2a/IgG1 ratio in Alum-immunized mice suggested a shift towards Th2 type immune response, but the presence of LcrE-specific IFN-γ-producing cells in LcrE+Alum-immunized mice also indicates Th1 type response. LcrE-specific IgA level was higher in both the sera and the lungs after using Freund's adjuvant. Phenotype of LcrE-specific IFN-γ-producing cells was CD4+ in Alum- and Freund's-immunized mice, but CD8+ cells were also detected in Freund's-immunized mice.These results confirm that LcrE induces protective immunity in mice. The results also show that Alum is able to activate the CD4+ cell-based cellular immunity, thus it can be regarded as an alternative adjuvant during vaccine screening and a useful adjuvant in a potential protein vaccine against C. pneumoniae infection.     

Association analysis of <Emphasis Type="Italic">SLC22A4</Emphasis>, <Emphasis Type="Italic">SLC22A5</Emphasis> and <Emphasis Type="Italic">DLG5</Emphasis> in Japanese patients with Crohn disease

Crohn disease (CD) is an inflammatory bowel disease characterized by chronic transmural, segmental, and typically granulomatous inflammation of the gut. Recently, two novel candidate gene loci associated with CD, SLC22A4 and SLC22A5 on chromosome 5 known as IBD5 and DLG5 on chromosome 10, were identified through association analysis of Caucasian CD patients. We validated these candidate genes in Japanese patients with CD and found a weak but possible association with both SLC22A4 (P=0.028) and DLG5 (P=0.023). However, the reported genetic variants that were indicated to be causative in the Caucasian population were completely absent in or were not associated with Japanese CD patients. These findings imply significant differences in genetic background with CD susceptibility among different ethnic groups and further indicate some difficulty of population-based studies.     

The Plasmodium vivax homologues of merozoite surface proteins 4 and 5 from Plasmodium falciparum are expressed at different locations in the merozoite

Merozoite surface proteins of Plasmodium falciparum are one major group of antigens currently being investigated and tested as malaria vaccine candidates. Two recently described P. falciparum merozoite surface antigens, MSP4 and MSP5, are GPI-anchored proteins that each contain a single EGF-like domain and appear to have arisen by an ancient gene duplication event. The genes are found in tandem on chromosome 2 of P. falciparum and the syntenic region of the genome was identified in the rodent malarias P. chabaudi, P. yoelii and P. berghei. In these species, there is only a single gene, designated MSP4/5 encoding a single EGF-like domain similar to the EGF-like domain in both PfMSP4 and PfMSP5. Immunization of mice with PyMSP4/5 provides mice with high levels of protection against lethal challenge with blood stage P. yoelii. In this study, we show that in P. vivax, which is quite phylogenetically distant from P. falciparum, both MSP4 and MSP5 homologues can be found with their relative arrangements with respect to the surrounding genes mostly preserved. However, the gene for MSP2, found between MSP5 and adenylosuccinate lyase (ASL) in P. falciparum, is absent from P. vivax. The PvMSP4 and PvMSP5 genes have a two-exon structure and encode proteins with potential signal and GPI anchor sequences and a single EGF-like domain near the carboxyl-terminus. Rabbit antisera raised against purified recombinant proteins show that each of the antisera react with distinct proteins of 62 kDa for PvMSP4 and 86 kDa for PvMSP5 in parasite lysates. Indirect immunofluorescence assays (IFA) localized PvMSP4 over the entire surface of P. vivax merozoites, as expected, whereas, the MSP5 homologue was found to be associated with an apical organellar location consistent with micronemes or over the polar prominence.     

Effect of deoxymannojirimycin and Brefeldin A onYersinia pseudotuberculosisinvasin–eukaryotic cell interaction

The cell surface receptors of theYersinia pseudotuberculosisinvasin protein are theα_3–6β₁integrins. Invasin and the extracellular matrix protein fibronectin bind to the same or closely located sites onα₅β₁integrin, although invasin bind with a much greater affinity. Invasin-integrin interaction promotes bacterial penetration into eukaryotic cells. Binding of fibronectin to its integrin receptor seems to be dependent on terminal oligosaccharides processing. In this paper, we have examined the effect of 1-deoxymannojirimycin (dMNJ), an inhibitor of Golgiα-mannosidases involved in processing of N-glycan precursors, and of Brefeldin A (BFA), a natural product of fungi which has profound effects on the structure and function of the Golgi apparatus, on invasin–cell interaction. We found that unlike fibronectin, the interaction of invasin with cells was resistance to dMNJ. However, preincubating cells with BFA caused a dose dependent inhibition of invasin-mediated cell entry, while cell invasion bySalmonella typhimuriumwas not affected.     

The A312L 5′-UTR of Chlorella virus PBCV-1 is a translational enhancer in Arabidopsis thaliana

PBCV-1 (Paramecium bursaria Chlorella virus) is a large double stranded DNA virus that replicates in certain eukaryotic chlorella like green algae. The PBCV-1 A312L gene encodes a 33-kDa protein whose function currently is unknown. The 5′-UTR of the A312L mRNA is 153 nucleotides, longer than the 5′-UTR in any other PBCV-1 gene. The sequence 5′-AAAC was repeated 17 times within 156 bp 5′ to the A312L gene start codon and this sequence was repeated 13 times continuously in the 5′-UTR of the mRNA. Recombinant genes were constructed in vector pBI121 that contained the A312L 5′-UTR, in both the forward and inverse-complement orientations, fused to the GUS gene under the control of the CaMV 35S promoter. These constructs were introduced into Arabidopsis thaliana and the results indicated that the A312L 5′-UTR functions as a translational enhancer only in the forward orientation. Overall, the ratio of GUS enzyme activity to GUS mRNA was 15-fold higher in constructs derived from the A312L 5′-UTR in the forward orientation as compared to constructs containing the 5′-UTR in the inverse-complement orientation or those lacking the A312L 5′-UTR.     

Cloning of serotonin 5-HT1 receptor subtypes from the chimpanzee, gorilla and Rhesus monkey and their agonist-induced guanosine 5′γS triphosphate binding

5-HT₁ receptor subtypes (_1B, _1D and _1F) have been implicated in migraine pathophysiology and their ligands have been examined for pharmacological actions in various experimental animal models. Considerable divergences exist, however, in their primary sequences between experimental animals and human, and additional models closer to human, such as non-human primates seem to be useful for migraine research. Earlier, we cloned the 5-HT_1D, and here 5-HT_1B and 5-HT_1F receptors from the chimpanzee, gorilla and Rhesus monkey, via polymerase chain reactions with their genomic DNAs and primers designed from the corresponding human receptors. Direct sequencing of PCR products showed that the 5-HT_1B receptors from the chimpanzee, gorilla and monkey differ from the human receptor by 0, 1 and 7 residues, respectively while 5-HT_1F receptors differ by 0, 3 and 10 residues, respectively. These divergent residues are mostly conservatively substituted and also largely confined to the N-terminal region and the 3rd intracellular loop, away from transmembrane segments and intracellular loops near membrane which are critical for ligand binding and G protein coupling. The chimpanzee 5-HT_1D, 5-HT_1B and monkey 5-HT_1F receptors, as heterologously expressed in human embryonic kidney 293 cells, showed robust agonist-induced guanosine 5′gamma ³⁵S triphosphate (GTPγ³⁵S) binding through activation of G proteins containing Gγ_i subunits. Moreover, pronounced inhibition of basal GTPγ³⁵S binding by methiothepin (an antagonist), representing constitutively active receptors, was observed with only 5-HT_1D. Overall, ligand binding and GTPγ³⁵S binding profiles for these primate receptors are comparable to those for the human receptors and validate non-human primates as useful models for human migraine research.