Immune Monitoring Reveals Fusion Peptide Priming to Imprint Cross-Clade HIV-Neutralizing Responses with a Characteristic Early B Cell Signature

The HIV fusion peptide (FP) is a promising vaccine target. FP-directed monoclonal antibodies from vaccinated macaques have been identified that neutralize up to ∼60% of HIV strains; these vaccinations, however, have involved ∼1 year with an extended neutralization-eclipse phase without measurable serum neutralization. Here, in 32 macaques, we test seven vaccination regimens, each comprising multiple immunizations of FP-carrier conjugates and HIV envelope (Env) trimers. Comparisons of vaccine regimens reveal FP-carrier conjugates to imprint cross-clade neutralizing responses and a cocktail of FP conjugate and Env trimer to elicit the earliest broad responses. We identify a signature, appearing as early as week 6 and involving the frequency of B cells recognizing both FP and Env trimer, predictive of vaccine-elicited breadth ∼1 year later. Immune monitoring of B cells in response to vaccination can thus enable vaccine insights even in the absence of serum neutralization, here identifying FP imprinting, cocktail approach, and early signature as means to improve FP-directed vaccine responses.

Consistent elicitation of cross-clade HIV-neutralizing responses achieved in guinea pigs after fusion peptide priming by repetitive envelope trimer boosting

The vaccine elicitation of broadly neutralizing responses is a central goal of HIV research. Recently, we elicited cross-clade neutralizing responses against the N terminus of the fusion peptide (FP), a critical component of the HIV-entry machinery. While the consistency of the elicited cross-clade neutralizing responses was good in mice, it was poor in guinea pigs: after seven immunizations comprising either envelope (Env) trimer or FP coupled to a carrier, serum from only one of five animals could neutralize a majority of a cross-clade panel of 19 wild-type strains. Such a low response rate—only 20%—made increasing consistency an imperative. Here, we show that additional Env-trimer immunizations could boost broad FP-directed neutralizing responses in a majority of immunized animals. The first boost involved a heterologous Env trimer developed from the transmitted founder clade C strain of donor CH505, and the second boost involved a cocktail that combined the CH505 trimer with a trimer from the BG505 strain. After boosting, sera from three of five animals neutralized a majority of the 19-strain panel and serum from a fourth animal neutralized 8 strains. We demonstrate that cross-reactive serum neutralization targeted the FP by blocking neutralization with soluble fusion peptide. The FP competition revealed two categories of elicited responses: an autologous response to the BG505 strain of high potency (~10,000 ID₅₀), which was not competed by soluble FP, and a heterologous response of lower potency, which was competed by soluble FP. While the autologous response could increase rapidly in response to Env-trimer boost, the heterologous neutralizing response increased more slowly. Overall, repetitive Env-trimer immunizations appeared to boost low titer FP-carrier primed responses to detectable levels, yielding cross-clade neutralization. The consistent trimer-boosted neutralizing responses described here add to accumulating evidence for the vaccine utility of the FP site of HIV vulnerability.

Epitope-based vaccine design yields fusion peptide-directed antibodies that neutralize diverse strains of HIV-1

A central goal of HIV-1 vaccine research is the elicitation of antibodies capable of neutralizing diverse primary isolates of HIV-1. Here we show that focusing the immune response to exposed N-terminal residues of the fusion peptide, a critical component of the viral entry machinery and the epitope of antibodies elicited by HIV-1 infection, through immunization with fusion peptide-coupled carriers and prefusion stabilized envelope trimers, induces cross-clade neutralizing responses. In mice, these immunogens elicited monoclonal antibodies capable of neutralizing up to 31% of a cross-clade panel of 208 HIV-1 strains. Crystal and cryoelectron microscopy structures of these antibodies revealed fusion peptide conformational diversity as a molecular explanation for the cross-clade neutralization. Immunization of guinea pigs and rhesus macaques induced similarly broad fusion peptide-directed neutralizing responses, suggesting translatability. The N terminus of the HIV-1 fusion peptide is thus a promising target of vaccine efforts aimed at eliciting broadly neutralizing antibodies.

Perceived self-efficacy and headache-related disability

BACKGROUND

Headache-specific self-efficacy refers to patients' confidence that they can take actions that prevent headache episodes or manage headache-related pain and disability. According to social cognitive theory, perceptions of self-efficacy influence an individual's adaptation to persistent headaches by influencing cognitive, affective, and physiological responses to headache episodes as well as the initiation and persistence of efforts to prevent headache episodes.

OBJECTIVE

The objective of the present study was to construct and validate a brief measure of headache specific self-efficacy and to examine the relationship between self-efficacy and headache-related disability.

METHODS

A sample of 329 patients seeking treatment for benign headache disorders completed the Headache Management Self-Efficacy Scale and measures of headache-specific locus of control, coping, psychological distress, and headache-related disability. A subset of 262 patients also completed 4 weeks of daily headache recordings.

RESULTS

As predicted, patients who were confident they could prevent and manage their headaches also believed that the factors influencing their headaches were potentially within their control. In addition, self-efficacy scores were positively associated with the use of positive psychological coping strategies to both prevent and manage headache episodes and negatively associated with anxiety. Multiple regression analyses revealed that headache severity, locus-of-control beliefs, and self-efficacy beliefs each explained independent variance in headache-related disability.

Psychosocial correlates and impact of chronic tension-type headaches

OBJECTIVES

To examine the psychosocial correlates of chronic tension-type headache and the impact of chronic tension-type headache on work, social functioning, and well-being.

METHODS

Two hundred forty-five patients (mean age = 37.0 years) with chronic tension-type headache as a primary presenting problem completed an assessment protocol as part of a larger treatment outcome study. The assessment included a structured diagnostic interview, the Medical Outcomes Study Short Form, Disability Days/Impairment Ratings, Recurrent Illness Impact Profile, Beck Depression Inventory, State-Trait Anxiety Inventory-Trait Form, Primary Care Evaluation for Mental Disorders, and the Hassles Scale Short Form. Comparisons were made with matched controls (N = 89) and, secondarily, with Medical Outcomes Study data for the general population, arthritis, and back problem samples.

RESULTS

About two thirds of those with chronic tension-type headache recorded daily or near daily (> or =25 days per month) headaches with few (12%) recording headaches on less than 20 days per month. Despite the fact that patients reported that their headaches had occurred at approximately the present frequency for an average of 7 years, chronic tension-type headache sufferers were largely lapsed consulters (54% of subjects) or current consulters in primary care (81% of consulters). Significant impairments in functioning and well-being were evident in chronic tension-type headache and were captured by each of the assessment devices. Although headache-related disability days were reported by 74% of patients (mean = 7 days in previous 6 months), work or social functioning was severely impaired in only a small minority of patients. Sleep, energy level, and emotional well-being were frequently impaired with about one third of patients recording impairments in these areas on 10 or more days per month. Most patients with chronic tension-type headache continued to carry out daily life responsibilities when in pain, although role performance at times was clearly impaired by headaches and well-being was frequently impaired. Chronic tension-type headache sufferers were 3 to 15 times more likely than matched controls to receive a diagnosis of an anxiety or mood disorder with almost half of the patients exhibiting clinically significant levels of anxiety or depression. Affective distress and severity of headaches (Headache Index) were important determinants of headache impact/impairment.

CONCLUSIONS

Chronic tension-type headache has a greater impact on individuals' lives than has generally been realized, with affective distress being an important correlate of impairment. If treatment is to remedy impairment in functioning, affective distress, as well as pain, thus needs to be addressed.

In vivo addition of poly(A) tail and AU-rich sequences to the 3' terminus of the Sindbis virus RNA genome: a novel 3'-end repair pathway

Alphaviruses are mosquito-transmitted RNA viruses that cause important diseases in both humans and livestock. Sindbis virus (SIN), the type species of the alphavirus genus, carries a 11.7-kb positive-sense RNA genome which is capped at its 5' end and polyadenylated at its 3' end. The 3' nontranslated region (3'NTR) of the SIN genome carries many AU-rich motifs, including a 19-nucleotide (nt) conserved element (3'CSE) and a poly(A) tail. This 3'CSE and the adjoining poly(A) tail are believed to regulate the synthesis of negative-sense RNA and genome replication in vivo. We have recently demonstrated that the SIN genome lacking the poly(A) tail was infectious and that de novo polyadenylation could occur in vivo (K. R. Hill, M. Hajjou, J. Hu, and R. Raju, J. Virol. 71:2693-2704, 1997). Here, we demonstrate that the 3'-terminal 29-nt region of the SIN genome carries a signal for possible cytoplasmic polyadenylation. To further investigate the polyadenylation signals within the 3'NTR, we generated a battery of mutant genomes with mutations in the 3'NTR and tested their ability to generate infectious virus and undergo 3' polyadenylation in vivo. Engineered SIN genomes with terminal deletions within the 19-nt 3'CSE were infectious and regained their poly(A) tail. Also, a SIN genome carrying the poly(A) tail but lacking a part or the entire 19-nt 3'CSE was also infectious. Sequence analysis of viruses generated from these engineered SIN genomes demonstrated the addition of a variety of AU-rich sequence motifs just adjacent to the poly(A) tail. The addition of AU-rich motifs to the mutant SIN genomes appears to require the presence of a significant portion of the 3'NTR. These results indicate the ability of alphavirus RNAs to undergo 3' repair and the existence of a pathway for the addition of AU-rich sequences and a poly(A) tail to their 3' end in the infected host cell. Most importantly, these results indicate the ability of alphavirus replication machinery to use a multitude of AU-rich RNA sequences abutted by a poly(A) motif as promoters for negative-sense RNA synthesis and genome replication in vivo. The possible roles of cytoplasmic polyadenylation machinery, terminal transferase-like enzymes, and the viral polymerase in the terminal repair processes are discussed.

RNA-RNA recombination in Sindbis virus: roles of the 3' conserved motif, poly(A) tail, and nonviral sequences of template RNAs in polymerase recognition and template switching

Sindbis virus (SIN), a mosquito-transmitted animal RNA virus, carries a 11.7-kb positive-sense RNA genome which is capped and polyadenylated. We recently reported that the SIN RNA-dependent RNA polymerase (RdRp) could initiate negative-strand RNA synthesis from a 0.3-kb 3'-coterminal SIN RNA fragment and undergo template switching in vivo (M. Hajjou, K. R. Hill, S. V. Subramaniam, J. Y. Hu, and R. Raju, J. Virol. 70:5153-5164, 1996). To identify and characterize the viral and nonviral sequences which regulate SIN RNA synthesis and recombination, a series of SIN RNAs carrying altered 3' ends were tested for the ability to produce infectious virus or to support recombination in BHK cells. The major findings of this report are as follows: (i) the 3'-terminal 20-nucleotides (nt) sequence along with the abutting poly(A) tail of the SIN genome fully supports negative-strand synthesis, genome replication, and template switching; (ii) a full-length SIN RNA carrying the 3'-terminal 24 nt but lacking the poly(A) tail is noninfectious; (iii) SIN RNAs which carry 3' 64 nt or more without the poly(A) tail are infectious and regain their poly(A) tail in vivo; (iv) donor templates lacking the poly(A) tail do not support template switching; (v) full-length SIN RNAs lacking the poly(A) tail but carrying 3' nonviral extensions, although debilitated to begin with, evolve into rapidly growing poly(A)-carrying mutants; (vi) poly(A) or poly(U) motifs positioned internally within the acceptor templates, in the absence of other promoter elements within the vicinity, do not induce the jumping polymerase to reinitiate at these sites; and (vii) the junction site selection on donor templates occurs independently of the sequences around the acceptor sites. In addition to furthering our understanding of RNA recombination, these studies give interesting clues as to how the alphavirus polymerase interacts with its 3' promoter elements of genomic RNA and nonreplicative RNAs. This is the first report that an in vitro-synthesized alphavirus RNA lacking a poly(A) tail can initiate infection and produce 3' polyadenylated viral genome in vivo.

Nonhomologous RNA-RNA recombination events at the 3' nontranslated region of the Sindbis virus genome: hot spots and utilization of nonviral sequences

The mechanism of RNA-RNA recombination at the 3' nontranslated region (3'NTR) of the Sindbis virus (SIN) genome was studied by using nonreplicative RNA precursors. The 11.7-kb SIN genome was transcribed in vitro as two nonoverlapping RNA fragments. RNA-1 contained the entire 11.4-kb protein coding sequence of SIN and also carried an additional 1.8-kb nonviral sequence at its 3' end. RNA-2 carried the remaining 0.26 or 0.3 kb of the SIN genome containing the 3'NTR. Transfection of these two fragments into BHK cells resulted in vivo RNA-RNA recombination and release of infectious SIN recombinants. Eighteen plaque-purified recombinant viruses were sequenced to precisely map the RNA-RNA crossover sites at the 3'NTR. Sixteen of the 18 recombinants were found to be genetically heterogeneous at the 3'NTR. Two major clustered sites within the 3'NTR of RNA-2 were found to be fused to multiple locations on the nonviral sequence of RNA-1, resulting in insertions of 10 to 1,085 nucleotides at the 3'NTR. Sequence analysis of crossover sites suggested only limited homology and heteroduplex-forming capability between substrate RNAs. Analysis of additional 23 recombinant viruses generated by mutagenized donor and acceptor templates supports the occurrence of recombination hot spots on donor templates. Introduction of a 17-nucleotide rudimentary replicase recognition signal in the acceptor template alone did not induce the polymerase to reinitiate at the 17-nucleotide signal. Interestingly, deletion of a 24-nucleotide hot spot locus on the donor template abolished crossover events at one of the two sites and allowed the polymerase to reinitiate at the 17-nucleotide replicase recognition signal inserted at the acceptor template. The possible roles of RNA-protein and RNA-RNA interactions in the differential regulation of apparent pausing, template selection, and reinitiation are discussed.

The cell cycle program of polypeptide labeling in Chlamydomonas reinhardtii

The cell cycle program of polypeptide labeling in syndhronous cultures of wild-type Chlamydomonas reinhardtii was analyzed by pulse-labeling cells with 35SO4 = or [3H]arginine at different cell cycle stages. Nearly 100 labeled membrane and soluble polypeptides were resolved and studied using one-dimensional sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. The labeling experiments produced the following results. (a) Total 35SO4 = and [3H]arginine incorporation rates varied independently throughout the cell cycle. 35SO4 = incorporation was highest in the mid-light phase, while [3H]arginine incorporation peaked in the dark phase just before cell division. (b) The relative labeling rate for 20 of 100 polypeptides showed significant fluctuations (3-12 fold) during the cell cycle. The remaining polypeptides were labeled at a rate commensurate with total 35SO4 = or [3H]arginine incorporation. The polypeptides that showed significant fluctuations in relative labeling rates served as markers to identify cell cycle stages. (c) The effects of illumination conditions on the apparent cell cycle stage-specific labeling of polypeptides were tested. Shifting light-grown asynchronous cells to the dark had an immediate and pronounced effect on the pattern of polypeptide labeling, but shifting dark-phase syndhronous cells to the light had little effect. The apparent cell cycle variations in the labeling of ribulose 1,5-biphosphate (RUBP)-carboxylase were strongly influenced by illumination effects. (d) Pulse-chase experiments with light-grown asynchronous cells revealed little turnover or inter-conversion of labeled polypeptides within one cell generation, meaning that major polypeptides, whether labeled in a stage-specific manner or not, do not appear transiently in the cell cycle of actively dividing, light-grown cells. The cell cycle program of labeling was used to analyze effects of a temperature-sensitive cycle blocked (cb) mutant. A synchronous culture of ts10001 was shifted to restrictive temperature before its block point to prevent it from dividing. The mutant continued its cell cycle program of polypeptide labeling for over a cell generation, despite its inability to divide.

Autoradiographic studies of nicotinic acid utilization in human-mouse heterokaryons and inhibition of utilization in newly-formed hybrid cells

Although most mammalian cell lines can utilize either nicotinic acid or nicotinamide for the biosynthesis of nicotinamide adenine dinucleotide (NAD), thymidine kinase-deficient, mouse 3T3-4F cells are unable to utilize nicotinic acid. When 3T3-4E cells were fused with human D98/AH2 cells, autoradiography showed that the resultant heterokaryons synthesized NAD from nicotinic acid at rates comparable to the human parental cell. The rate of nicotinic acid utilization in heterokaryons remained unchanged over the four-day period of study following cell fusion. In contrast to the results observed with heterokaryons, nicotinic acid utilization was markedly reduced in hybrid cells. Of 100 hybrid clones examined at four or five days following cell fusion, 60 utilized nicotinic acid at rates less than one tenth that of the parental human cell. Similar results were observed in hybrid clones at nine or ten days following fusion. Uniformly high rates of NAD biosynthesis were observed in hybrid clones with nicotinamide as the precursor. This excludes the possibility that the reduction in nicotinic acid utilization in hybrid cells is due to a general metabolic dysfunction. The biochemical mechanism by which nicotinic acid utilization is markedly reduced has not been determined with certainty, however, several observations suggest genetic suppression.

Intravenous infusions of heparin and penicillins

The chemical stability and anticoagulant activity of heparin (20 U/ml) were studied in five intravenous fluids at room temperature. Heparin remained stable and active for 24 hours in normal saline, but there was a rapid inactivation of 40 to 55% in solutions containing dextrose or lactate, as measured by chemical and biological methods.High concentrations of benzylpenicillin, ampicillin, or methicillin had no effect on heparin activity in normal saline or dextrose 5%: nor was the stability of the penicillins in these fluids affected to any marked extent by the presence of heparin. Ampicillin was, however, found to be unstable in dextrose 5%, and it would be preferable for it not to be added to dextrose infusions. It is concluded that heparin may be given intravenously in normal saline with benzylpenicillin, ampicillin, or methicillin but several other antibiotics were found to be unsuitable for concurrent infusion with heparin.

Sex pheromone of the codling moth: structure and synthesis

The structure of a sex pheromone of the codling moth. Laspeyresia pomonella (L.), has been determined by spectrometric and chemical degradative techniques and by synthesis to be (2Z, 6E)-7-methyl-3-propyl-2,6-decadien-1-ol. In field cage tests the synthesized sex pheromone was as attractive as the natural, but neither was as attractive as ten virgin females per trap.

Chromatograms of Foods for Multicomponent Residue Determination of Pesticides Containing Phosphorus and/or Sulfur by GLC with Flame Photometric Detection

As part of an effort to devise a multicomponent pesticide residue analysis, temperature programmed gas chromatography with the Melpar flame photometric detector was used to obtain chromatograms of extracts of 39 repsentative foods on the thermally stable OV-101 and OV-210 packings. The chromatograms, which show where interference occurs with each food, supplement data previously reported on the retention times of 138 pesticides and metabolites containing phosphorus and sulfur in their molecules. Thus, where interferences from a food are absent, observation of pesticide peaks is possible. Food samples were extracted by one of 4 methods and then partitioned between hexane and acetonitrile by one of 2 procedures prior to analysis by gas chromatography. Very little interference was seen in the chromatograms of about 90% of the food extracts in the P mode and about two-thirds of the food extracts in the S mode; except for high fat samples, weights of co-extractives were also generally small. The lower limit of detection for most pesticides was estimated to be 0.01–0.05 ppm in the P mode and 0.02–0.1 ppm in the S mode. Analysis using the S mode has limited applicability because of the large samples needed to offset the lesser sensitivity of the S detector and the resulting contamination of the chromatographic column by coextractives. Analysis using the P mode is considered practical now. Retention time data on 8 additional pesticidal compounds are also reported.

Portal hypertension in acute experimental veno-occlusive disease of the liver in rats

Portal pressure was measured in rats 1-14 days after an LD₅₀ of dimethylnitrosamine (DMN). A significant rise of portal pressure was found at 5 and 7 days after the dose. Veno-occlusive lesions do not occur before 7 days in these animals. Control observations on rats receiving CCl₄ showed no change in portal pressure attributable to centrilobular necrosis. Possible mechanisms for this rise of pressure are discussed.