DNA vaccination with KMP11 and Lutzomyia longipalpis salivary protein protects hamsters against visceral leishmaniasis

It was recently shown that immunization of hamsters with DNA plasmids coding LJM19, a sand fly salivary protein, partially protected against a challenge with Leishmania chagasi, whereas immunization with KMP11 DNA plasmid, a Leishmania antigen, induced protection against L. donovani infection. In the present study, we evaluated the protective effect of immunization with both LJM19 and KMP11 DNA plasmid together. Concerning the protection against an infection by L. chagasi, immunization with DNA plasmids coding LJM19 or KMP11, as well as with both plasmids combined, induced IFN-γ production in draining lymph nodes at 7, 14 and 21 days post-immunization. Immunized hamsters challenged with L. chagasi plus Salivary Gland Sonicate (SGS) from Lutzomyia longipalpis showed an enhancement of IFN-γ/IL-10 and IFN-γ/TGF-β in draining lymph nodes after 7 and 14 days of infection. Two and five months after challenge, immunized animals showed reduced parasite load in the liver and spleen, as well as increased IFN-γ/IL-10 and IFN-γ/TGF-β ratios in the spleen. Furthermore, immunized animals remained with a normal hematological profile even five months after the challenge, whereas L. chagasi in unimmunized hamsters lead to a significant anemia. The protection observed with LJM19 or KMP11 DNA plasmids used alone was very similar to the protection obtained by the combination of both plasmids.     

Putative rhesus macaque germline predecessors of human broadly HIV-neutralizing antibodies: differences from the human counterparts and implications for HIV-1 vaccine development

Broadly neutralizing antibodies (bnAbs) are likely to be a key component of protective immunity conferred by an effective HIV-1 vaccine. We and others have reported that putative human germline predecessors of known human bnAbs lack measurable binding to HIV-1 envelope glycoproteins (Env), which could be a new challenge for eliciting human bnAbs. Rhesus macaques have been used as nonhuman primate models for testing vaccine candidates, but little is known about their germline Abs. Here we show the similarities and differences between putative rhesus macaque and human germline predecessors and possible intermediate antibodies of one of the best characterized bnAbs, b12. Similar to the human counterpart, a putative rhesus macaque b12 germline antibody lacks measurable binding to HIV-1 Envs, suggesting that initiation of somatic maturation of rhesus macaque germline b12 predecessor may also be a challenge. However, differences in sequence characteristics and binding properties between macaque and human b12 germline and intermediate antibodies suggest that the two germline predecessors may undergo different maturation pathways in rhesus macaques and in humans. These results indicate that immunogens that could initiate the immune responses and drive somatic mutations leading to elicitation of b12 or b12-like bnAbs in rhesus macaques and in humans are likely to be different. This has important implications for HIV-1 vaccine development.     

Control of sensory transmission by electrical stimulation within the caudal raphe nuclei of the cat

These experiments used evoked potential techniques to define further the role of neurons in the caudal raphe nuclei (CRN) in the control of sensory transmission. In each experiment, single-pulse, low-intensity stimuli were tested for the ability to change the amplitude of potentials in the spinothalamic tract (ST) and medial lemniscus (ML) evoked by superficial radial nerve stimulation. It was shown that the effect of CRN stimulation was directed specifically to neurons of the ST because only a small and variable effect was seen on the sensory-evoked potential in the ML. Also, CRN sites were located in two discontinuous regions where electrical stimulation was most effective in inhibiting sensory-evoked activity in the ST. Finally, it was shown that the effect on inhibition of the ST included activity carried by both large-diameter and small-diameter primary afferent fibers.     

Strategic evaluation of vaccine candidate antigens for the prevention of Visceral Leishmaniasis

Infection with Leishmania parasites results in a range of clinical manifestations and outcomes, the most severe of which is visceral leishmaniasis (VL). Vaccination will likely provide the most effective long-term control strategy, as the large number of vectors and potential infectious reservoirs renders sustained interruption of Leishmania parasite transmission extremely difficult. Selection of the best vaccine is complicated because, although several vaccine antigen candidates have been proposed, they have emerged following production in different platforms. To consolidate the information that has been generated into a single vaccine platform, we expressed seven candidates as recombinant proteins in E. coli. After verifying that each recombinant protein could be recognized by VL patients, we evaluated their protective efficacy against experimental L. donovani infection of mice. Administration in formulation with the Th1-potentiating adjuvant GLA-SE indicated that each antigen could elicit antigen-specific Th1 responses that were protective. Considering the ability to reduce parasite burden along with additional factors such as sequence identity across Leishmania species, we then generated a chimeric fusion protein comprising a combination of the 8E, p21 and SMT proteins. This E. coli –expressed fusion protein was also demonstrated to protect against L. donovani infection. These data indicate a novel recombinant vaccine antigen with the potential for use in VL control programs.     

抗乙型肝炎病毒Pre S2 3B9单克隆抗体轻链可变区基因的扩增及序列分析

为了构建基因工程抗体并从分子水平分析抗乙型肝炎病毒ＰｒｅＳ２３Ｂ９单克隆抗体，我们利用分子生物学技术快速分离３Ｂ９杂交瘤细胞总ＲＮＡ，经反转录，ＰＣＲ扩增，分离获得了３Ｂ９单抗轻链可变区基因，并用聚合酶链反应（ＰＣＲ）技术及双脱氧核苷酸链末端终止法对该可变区基因的全部３２７ｂｐ核苷酸序列进行了测定。结果表明，３Ｂ９单抗轻链隶属小鼠免疫球蛋白Ｋａｐｐａ轻链第Ⅱ亚组，ＪＫ１微基因重排。     

Anterograde tracer and field potential analysis of the neocortical layer I projection from nucleus ventralis medialis of the thalamus in cat

The projection of the ventromedial nucleus of the thalamus to the neocortex was studied in cat by means of anterograde and retrograde transport of horseradish peroxidase, by the depth profile of evoked thalamocortical field potentials, and by superfusion of the cortex with manganese to block transmitter release. Horseradish peroxidase injected into the ventromedial nucleus was anterogradely transported to the outer third of layer I in the neocortex, extending from the depth of the cruciate sulcus anterior to the olfactory bulb and tract. The region of projection from the ventromedial nucleus extended mediolaterally from the medial wall of the proreus gyrus to the ventral tip of the coronal gyrus. Horseradish peroxidase injections or applications in these areas of the neocortex resulted in the retrograde labeling of neurons in the ventromedial nucleus. Injections in many other cortical areas did not result in labeled neurons in this nucleus. Stimulation of the ventromedial nucleus with single pulses elicited surface-negative waves in the medial part of the precruciate region that had superficial isoelectric points. Superfusion of the precruciate area with manganese resulted in the suppression of the ventromedial-evoked wave, whereas control extracellular waves in deeper layers were unaffected. An additional additional finding was that horseradish peroxidase injections in the ventromedial nucleus led to a dense reciprocal retrograde labeling of neurons in layer VI of that part of the cortex to which the ventromedial nucleus projects. We conclude that, in cat, (1) the ventromedial nucleus projects to layer I of the cerebral cortex anterior to the cruciate sulcus and receives a dense reciprocal projection from layer VI; (2) stimulation of neurons in the ventromedial nucleus causes depolarization of structures in layer I and these neurons are responsible for recruiting responses in the anterior cortex.     

Projections of the pallidal complex: An autoradiographic study in the cat

The efferent projections of the external pallidal segment (‘globus pallidus’), and the internal pallidal segment (entopeduncular nucleus) were studied in separate experiments in the cat by the auto-radiographic tracing method. Injections of tritiated amino acids into the external pallidal segment resulted in labelling of axon systems distributed not only to the subthalamic nucleus but also in sparser density to the nucleus reticularis thalami, the substantia nigra, the caudate nucleus, the putamen, and as yet undefined areas of the cortex. Injections of tritiated amino acids into the internal pallidal segment resulted in labelling of axon systems distributed to the ventrolateral-ventroanterior complex of the thalamus, to the centrum medianum, the lateral habenular nucleus, and the mesencephalic nucleus tegmenti pedunculopontinus, pars compacta. Less prominent termination may also occur in the parafas-cicular nucleus, the nuclei of the fields of Forel, and in the mesencephalic tegmentum rostral to the nucleus tegmenti pedunculopontinus, pars compacta.The fact that this and previous studies show that the projections of the pallidal complex are more widespread than would be expected if it was only involved in motor functions, raises questions about the functional organization of the basal ganglia. These are discussed in the following paper.