Surprising negative association between IgG1 allotype disparity and anti-adalimumab formation: a cohort study

Introduction

The human monoclonal antibody adalimumab is known to induce an anti-globulin response in some adalimumab-treated patients. Antibodies against adalimumab (AAA) are associated with non-response to treatment. Immunoglobulins, such as adalimumab, carry allotypes which represent slight differences in the amino acid sequences of the constant chains of an IgG molecule. Immunoglobulins with particular IgG (Gm) allotypes are racially distributed and could be immunogenic for individuals who do not express these allotypes. Therefore, we investigated whether a mismatch in IgG allotypes between adalimumab and IgG in adalimumab-treated patients is associated with the development of AAA.

Methods

This cohort study consisted of 250 adalimumab-treated rheumatoid arthritis (RA) patients. IgG allotypes were determined for adalimumab and for all patients. Anti-idiotype antibodies against adalimumab were measured with a regular radio immunoassay (RIA), and a newly developed bridging enzyme linked immunosorbent assay (ELISA) was used to measure anti-allotype antibodies against adalimumab. The association between AAA and the G1m3 and the G1m17 allotypes was determined. For differences between groups we used the independent or paired samples t-test, Mann-Whitney test or Chi square/Fisher's exact test as appropriate. To investigate the influence of confounders on the presence or absence of AAA a multiple logistic regression-analysis was used.

Results

Adalimumab carries the G1m17 allotype. No anti-allotype antibodies against adalimumab were detected. Thirty-nine out of 249 patients had anti-idiotype antibodies against adalimumab (16%). IgG allotypes of RA patients were associated with the frequency of AAA: patients homozygous for G1m17 had the highest frequency of AAA (41%), patients homozygous for G1m3 the lowest frequency (10%), and heterozygous patients' AAA frequency was 14% (P = 0.0001).

Conclusions

An allotype mismatch between adalimumab and IgG in adalimumab-treated patients did not lead to a higher frequency of AAA. On the contrary, patients who carried the same IgG allotype as present on the adalimumab IgG molecule, had the highest frequency of anti-adalimumab antibodies compared to patients whose IgG allotype differed from adalimumab. This suggests that the allotype of adalimumab may not be highly immunogenic. Furthermore, patients carrying the G1m17-allotype might be more prone to antibody responses.     

The strength of the HIV-1 3' splice sites affects Rev function

Background

Of the diverse subtypes of Human Immunodeficiency Virus Type-1 (HIV-1), subtype-C strains cause a large majority of infections worldwide. The reasons for the global dominance of HIV-1 subtype-C infections are not completely understood. Tat, being critical for viral infectivity and pathogenesis, may differentially modulate pathogenic properties of the viral subtypes. Biochemical studies on Tat are hampered by the limitations of the current purification protocols. Tat purified using standard protocols often is competent for transactivation activity but defective for a variety of other biological functions. Keeping this limitation in view, we developed an efficient protein purification strategy for Tat.

Results

Tat proteins obtained using the novel strategy described here were free of contaminants and retained biological functions as evaluated in a range of assays including the induction of cytokines, upregulation of chemokine coreceptor, transactivation of the viral promoter and rescue of a Tat-defective virus. Given the highly unstable nature of Tat, we evaluated the effect of the storage conditions on the biological function of Tat following purification. Tat stored in a lyophilized form retained complete biological activity regardless of the storage temperature. To understand if variations in the primary structure of Tat could influence the secondary structure of the protein and consequently its biological functions, we determined the CD spectra of subtype-C and -B Tat proteins. We demonstrate that subtype-C Tat may have a relatively higher ordered structure and be less flexible than subtype-B Tat. We show that subtype-C Tat as a protein, but not as a DNA expression vector, was consistently inferior to subtype-B Tat in a variety of biological assays. Furthermore, using ELISA, we evaluated the anti-Tat antibody titers in a large number of primary clinical samples (n = 200) collected from all four southern Indian states. Our analysis of the Indian populations demonstrated that Tat is non-immunodominant and that a large variation exists in the antigen-specific antibody titers.

Conclusion

Our report not only describes a simple protein purification strategy for Tat but also demonstrates important structural and functional differences between subtype-B and -C Tat proteins. Furthermore, this is the first report of protein purification and characterization of subtype-C Tat.     

Olfaction in infants and children: developmental and functional perspectives

This paper reviews some studies related to the ontogeny of olfactorycompetence in humans from the foetal – neonatal to thepubertal period. Psychophysical and hedonk studies of developingolfactory function demonstrate keen detection and discriminationabilities from birth onwards. Although the sensory parametersof infantile olfaction nearly equal those of mature function,developmental processes seemingly act upon the hedonic integrationof odours. From the first post-natal week, infants rely on thisolfactory competence in social contexts: olfactory cues derivedfrom conspecifics' body chemistry are used to differentiatefamiliar from unfamiliar individuals or kin from non-kin. Additionalstudies are needed, however, to demonstrate an early recognitionof olfactory individuality by young infants. The infants' discriminativeperformance in regard to social odours and the incentive valuethey assign to them are progressively specified in close relationshipwith the earliest social experiences. To date, the salienceof olfactory stimulations has been poorly documented in theinfants' normal life. But clinical evidence underlines theirpotential involvement (i) in the earliest infant–motherbonding processes, (ii) in the infant's emotional homeostasisand (iii) in the child's interactional adjustments.     

Behavioural, growth and immune consequences of early weaning in one-week-old large-white piglets.

Genetic improvement in sows' prolificity is limited by their milk capacities, which do not allow all piglets to survive or grow normally. This experiment compared the behaviour, growth and immune responses of piglets that were weaned early at 6 days of age (EW) vs. control Large White piglets' (C) suckled by their mothers. Behaviour of 9 litters of 5 to 8 piglets in each group were observed from d5 to d20. All piglets were weighed from birth to d74. Three piglets from each group were slaughtered on d36 for immunological analysis. Until they began to eat dry food, EW piglets walked and vocalised more than C piglets. After that time, when resting, they were less often lying down and more frequently in contact with littermates under the heater. Aggressive behaviour and belly-nosing were more frequent. They displayed a more marked growth check after weaning than did C piglets until 28 days of age. In EW piglets, at 36 days of age, there was a higher density of T- and B-lymphocytes in the gut epithelium and lamina propria, fespectively, in relation to the size of lymphoid follicles of Peyer's patches. The results indicate great behavioural adaptation capacities of very early-weaned piglets, together with earlier maturation of their gut immune system.     

雅鲁藏布江中游浮游植物群落优势种时空生态位

为探究雅鲁藏布江中游浮游植物群落分布格局及其优势种时空生态位特征,于2021年7月、10月对该水域进行浮游植物样品的采集和水体理化因子的测定,鉴定浮游植物物种,计算浮游植物优势种生态位宽度、生态位重叠值、生态响应速率及相对资源占有率,运用共现网络模型分析群落的种间关联性,并对浮游植物优势种与环境因子进行Pearson相关性分析。结果表明：该水域共鉴定到浮游植物644种,隶属于8门12纲25目49科152属,其中,优势种22种,优势种中硅藻占90.9%,在群落中占绝对优势;丰水期的肘状针杆藻丰度最大(74.193×10⁴细胞/L)且出现频率最高(0.867),是丰水期绝对优势种;整体上优势种生态位宽度时间(0.833)>空间(0.254),优势种时空生态位宽度主要受空间生态位宽度的影响,空间异质性是影响该水域浮游植物优势种分布的主要因素;优势种时空二维生态位无意义重叠的种对占40.69%,优势种时空二维的生态位重叠以中、低等级为主,优势种间对时空资源需求异质性高,种间潜在竞争关系较弱;该水域枯水期浮游植物群落的网络结构紧密,群落连通性、群落复杂度和物种间生态位...     

棉蚜体色变化的生态遗传学研究

调查了不同寄主上棉蚜刀Aphis gossypll自受精卵孵化出的自然种群、室内混合饲养以及单个饲养蚜虫的体色变化。结果表明：不论是自然还是实验种群,是群体还是个体饲养,不论寄主、栽培条件、生育期营养相同与否,棉蚜体色在世代内稳定不变,即出生时是什么颜色保持终生不变;在世代间则随温度升高体色渐变为黄色,温度降低体色逐渐转绿。伏蚜由苗蚜而来。X²检验证实：棉蚜体色变化与营养、寄主种类、光照、光质、栽培条件等无关,仅与温度密切相关,属于同一基因型在不同环境条件下的反应规范。但在太槿上还发现有个别深黄色棉蚜,从卵孵化到迁飞体色不随温度变化,表明棉蚜体色变化中还存在遗传多态现象。胚胎学观察与染色体校型分析结果证实了上述结论与观点。     

DNA “FINGERPRINTS” REVEAL GENOTYPIC DISTRIBUTIONS IN NATURAL POPULATIONS OF BLACKBERRIES AND RASPBERRIES (RUBUS,ROSACEAE)

The genotypic distributions in a population of Rubus occidentalis L. and R. pensilvanicus Poiret were analyzed by using DNA “fingerprinting.” The number of genotypes found was related to the mode of reproduction; 20 plants of the sexual R. occidentalis comprised 15 genotypes, whereas 20 plants of the presumably apomictic R. pensilvanicus comprised only five genotypes. DNA “fingerprinting” appears to be a useful tool in the understanding of population structure.     

In situ hybridization at the electron microscope level: hybrid detection by autoradiography and colloidal gold

In situ hybridization has become a standard method for localizing DNA or RNA sequences in cytological preparations. We developed two methods to extend this technique to the transmission electron microscope level using mouse satellite DNA hybridization to whole mount metaphase chromosomes as the test system. The first method devised is a direct extension of standard light microscope level using mouse satellite DNA hybridization to whole mount metaphase chromosomes as the test system. The first method devised is a direct extension of standard light microscope in situ hybridization. Radioactively labeled complementary RNA (cRNA) is hybridized to metaphase chromosomes deposited on electron microscope grids and fixed in 70 percent ethanol vapor; hybridixation site are detected by autoradiography. Specific and intense labeling of chromosomal centromeric regions is observed even after relatively short exposure times. Inerphase nuclei present in some of the metaphase chromosome preparations also show defined paatterms of satellite DNA labeling which suggests that satellite-containing regions are associate with each other during interphase. The sensitivity of this method is estimated to at least as good as that at the light microscope level while the resolution is improved at least threefold. The second method, which circumvents the use of autoradiogrphic detection, uses biotin-labeled polynucleotide probes. After hybridization of these probes, either DNA or RNA, to fixed chromosomes on grids, hybrids are detected via reaction is improved at least threefold. The second method, which circumvents the use of autoradiographic detection, uses biotin-labeled polynucleotide probes. After hybridization of these probes, either DNA or RNA, to fixed chromosomes on grids, hybrids are detected via reaction with an antibody against biotin and secondary antibody adsorbed to the surface of over centromeric heterochromatin and along the associated peripheral fibers. Labeling is on average ten times that of background binding. This method is rapid and possesses the potential to allow precise ultrastructual localization of DNA sequences in chromosomes and chromatin.     

Use of a crude extract or purified antigen from first‐instar cattle grubs,Hypoderma lineatum,for the detection of anti‐Hypoderma antibodies in free‐ranging cervids from southern Spain

During the 2003–2005 hunting seasons, a total of 120 Cervidae, including 39 red deer (Cervus elaphus hispanicus) and 81 fallow deer (Dama dama), were examined for subcutaneous myiasis. Animals were shot from January to June in southern Spain. Specific antibodies against Hypodermatinae (Diptera: Oestridae) were detected by indirect enzyme‐linked immunosorbent assay (iELISA) using a crude larval extract (CLE) and a purified antigen [hypodermin C (HC)] obtained from first instars of Hypoderma lineatum (De Villers) (Diptera: Oestridae). Hypoderma actaeon Brauer was the only species detected in this study, which represents the first confirmation of this species in fallow deer from Spain. The overall prevalence of animals presenting subcutaneous larvae (14.2%) was considerably lower than the prevalences determined by iELISA with CLE (43.3%) and HC (40.0%). Red deer showed a higher prevalence of Hypoderma than fallow deer. The concordance between larval examination during the hunting season and iELISA using both antigens was low, whereas the concordance between the CLE and HC ELISAs was good. Larval antigens obtained from H. lineatum constitute a good tool for the diagnosis of H. actaeon in Cervidae, especially when the hunting season does not coincide with the maximum presence of larvae on the back.