Regulation of BCR signal transduction in B-1 cells requires the expression of the Src family kinase Lck

Although found predominantly in the peritoneal and pleural cavities, B-1 cells are also present in other peripheral tissues such as spleen and lung. While similar in surface phenotypes, such as CD5, all B-1 cells are not equivalent in their response to stimuli. Here, we report that the src family kinase Lck is required to confer the BCR hyporesponsiveness typical of CD5+ B-1 cells and appears involved in the maintenance of their unique function. Splenic B-1 cells express CD5 but not Lck and are not hyporesponsive; however, within the peritoneum, these B-1 cells are induced to express Lck and acquire a hyporesponsive phenotype. Peritoneal B-1 cells from lck-deficient mice, while CD5+, no longer exhibit attenuated BCR signaling. Interestingly, lck-null mice exhibited increased natural antibody levels characteristic of B-1 cells. Taken together, these results demonstrate a key role for Lck in modulating the signaling and cellular fate of B-1 B cells.     

Impact of suppression of viral replication by highly active antiretroviral therapy on immune function and phenotype in chronic HIV-1 infection

We compared immune phenotypes, lymphocyte proliferation (LP), and delayed type hypersensitivity (DTH) responses in 28 male antiretroviral treatment-naive and experienced HIV-1-infected patients, matched pair-wise according to age and CD4+ T-lymphocyte count. Median CD4+ T-lymphocyte counts were 441 cells/microL and 483 cells/microL and median CD4+ T-lymphocyte nadirs were 435 cells/microL and 150 cells/microL in both groups, respectively. Absolute numbers of circulating T-lymphocyte subpopulations and proportions of naive and memory T-lymphocytes were comparable in the two groups. Untreated patients had greater proportions of activated CD4+ (p <.05) and CD8+ (p <.01) T-cells expressing human leukocyte antigen (HLA)DR and CD38 and fewer CD8+ cells expressing CD28 (p <.05). DTH and LP responses were comparable in both groups except for HIVp24, LP responses, and mumps DTH responses, which were of greater magnitude in the group treated with highly active antiretroviral therapy (HAART) (p <.05). Thus, HIV-1-infected patients who experienced substantial increases in CD4+ T-lymphocyte counts after suppression of viral replication on HAART had fewer activated lymphocytes and similar immune function when compared with findings in untreated patients with similar CD4+ T-cell counts. HIV replication has minimal real-time effect on CD4+ T-cell function in response to non-HIV antigens but helper T-cell responses to HIV-gag antigen are impaired during ongoing viral replication and may be restored by antiretroviral therapy.     

Assessment of changes in penile sensation by electrophysiological study after radical prostatectomy: A pilot study

Background:To evaluate the changes in penile sensation by electrophysiological tests in patients who underwent radical prostatectomy (RP) and to demonstrate the role of dorsal penile nerve injury in postoperative erectile dysfunction.Materials and methods:Twenty-six volunteer patients who were eligible for RP were included in the study. Preoperative penile sensory electromyography and the International Index of Erectile Function-5 (IIEF-5) questionnaire were done for each patient. Erectile function assessment and electrophysiological evaluation of penile sensation were repeated at postoperative 3rd and 6th months.Results:Postoperative IIEF-5 scores and electromyography values were significantly lower than preoperative findings (p < 0.05). The IIEF-5 scores in the nerve sparing-RP (NS-RP) group were significantly higher than the non-nerve sparing-RP (NNS-RP) group in the postoperative period. Nerve conduction velocity values in the NS-RP group were also higher than the NNS-RP group at the postoperative 3rd and 6th months. However, these changes were not statistically significant (p > 0.05).Conclusions:Patients who underwent RP have decreased penile sensation due to cavernous nerve damage and a possible dorsal penile nerve injury. The decrease of penile sensation may be associated with postoperative erectile dysfunction.     

Binding of lipopeptide to CD14 induces physical proximity of CD14, TLR2 and TLR1

Lipoproteins or lipopeptides (LP) are bacterial cell wall components detected by the innate immune system. For LP, it has been shown that TLR2 is the essential receptor in cellular activation. However, molecular mechanisms of LP recognition are not yet clear. We used a FLAG-labeled derivative of the synthetic lipopeptide N-palmitoyl-S-[2,3-bis(palmitoyloxy)-(2R,S)-propyl]-(R)-cysteinyl-seryl-(lysyl)(3)-lysine (Pam(3)CSK(4)) to study the roles of CD14, TLR2 and TLR1 in binding and signaling of LP and their molecular interactions in human cells. The activity of Pam(3)CSK(4)-FLAG was TLR2 dependent, whereas the binding was enabled by CD14, as evaluated by flow cytometry and confocal microscopy. Using FRET and FRAP imaging techniques to study molecular associations, we could show that after Pam(3)CSK(4)-FLAG binding, CD14 and Pam(3)CSK(4)-FLAG associate with TLR2 and TLR1, and TLR2 is targeted to a low-mobility complex. Thus, LP binding to CD14 is the first step in the LP recognition, inducing physical proximity of CD14 and LP with TLR2/TLR1 and formation of the TLR2 signaling complex.     

Pilot study of an HLA-A2 peptide vaccine using flt3 ligand as a systemic vaccine adjuvant

A pilot vaccine study was conducted to test the safety and immunological efficacy of four monthly immunizations of an MHC class I peptide vaccine, the E75 HLA-A2 epitope from HER-2/neu, using flt3 ligand as a systemic vaccine adjuvant. Twenty HLA-A2-expressing subjects with advanced stage prostate cancer were randomly assigned to one of four immunization or treatment schedules: (a) Flt3 ligand (20 g/kg per day) administered subcutaneously daily for 14 days on a 28-day cycle, monthly for four months; (b) flt3 ligand course as above with the E75 peptide vaccine administered on day 7 of each flt3 ligand cycle; (c) flt3 ligand course as above with the E75 peptide vaccine administered on day 14 of each flt3 ligand cycle; or (d) E75 peptide admixed with granulocyte–macrophage colony-stimulating factor and administered intradermally once every 28 days, as has previously been reported. The primary endpoints of the study were the determination of safety and immunological efficacy in generating E75-specific T cells as determined by peptide-specific interferon-gamma ELIspot. Adverse events included one grade 3 skin reaction and the development of grade 2 autoimmune hypothyroidism in two subjects with preexisting subclinical autoimmune hypothyroidism. Dendritic cells were markedly increased in the peripheral blood of subjects receiving flt3 ligand with each repetitive cycle, but augmentation of antigen-presenting cells within the dermis was not observed. Apart from a single subject, no significant peptide-specific T-cell responses were detected by ELIspot, whereas delayed-type hypersensitivity responses were detectable in control subjects and in subjects receiving peptide vaccine early in the course of flt3 ligand administration. The absence of robust peripheral immune responses in the current study may be attributable to the small numbers of subjects or differences in the subject population. In addition, the inability of flt3 ligand to augment the number of peripheral skin antigen-presenting cells may have contributed to the absence of robust peptide-specific immunity detectable in the peripheral blood of immunized subjects treated with flt3 ligand.     

An Evaluation of Breastfeeding Promotion Through Peer Counseling in Mississippi WIC Clinics

Objective: This study evaluates the effectiveness of a peer counseling program at increasing breastfeeding by participants in the Mississippi Special Supplemental Nutrition Program for Women, Infants and Children (WIC). Methods: Data from the 1989–1993 Pediatric Nutrition Surveillance System were analyzed to compare breastfeeding rates in clinics with and without peer counseling programs. A questionnaire completed by program staff to describe the program in greater detail helped identify characteristics associated with greater success. Results: The incidence of breastfeeding rose from 12.3% to 19.9% in those clinics with peer counseling programs, but only from 9.2% to 10.7% in clinics without a program. Clinics that started a program earlier showed greater changes in breastfeeding incidence. However, the presence of lactation specialists or consultants in the clinic appeared to be more important than the presence of less-trained peer counselors. Peer counselors who spent more than 45 minutes per participant were more effective than those spending less time. Conclusions: The peer counseling program significantly increased the incidence of breastfeeding, particularly in clinics with lactation specialists and consultants. Success can be enhanced by ensuring that peer counselors spend a great deal of time with the participants.     

Is the Degree of Arrhythmia Suppression a Predictor of Survival?

The effectiveness of an antiarrhythmic drug is judged by the degree of ventricular arrhythmia suppressed by the drug. It has been suggested that a certain degree of ventricular arrhythmia suppression should be targeted to prove efficacy. Targets used to define the effectiveness of an antiarrhythmic agent included an 80% reduction in the ventricular premature complexes (VPCs) and 90% suppression of nonsustained ventricular tachycardia (NVT) episodes or complete abolition of runs of sustained VT (SVT) [1]. Other dose-adjusted antiarrhythmic trials have attempted to achieve either isolated control of the PVCs of greater-than-or-equal70% [2--5] with the suppression of the high grades of arrhythmia such as couplets and NVT of >90% and 100%, respectively [2, 3]. Such targets of arrhythmia suppression were recommended to avoid errors encountered with the occurrence of the spontaneous variability of ventricular arrhythmia and to be confident that antiarrhythmic therapy has produced a true drug effect [6]. Presently, there is no evidence that suppression of these arrhythmias with type I antiarrhythmic drugs is likely to reduce sudden death [4, 6]. The survival of patients with frequent VPCs and high-grade forms (couplets [C], NVT) and organic heart disease is not dependent on the degree of arrhythmia suppression. The survival of patients with low LVEF of <40% and runs of NVT is improved and is similar to that of patients with good LVEF of greater-than-or-equal40%. Such a lack of correlation between arrhythmia suppression and survival might be a unique feature of the antifibrillatory drugs and might not be applied to the antiectopic drugs. If a high degree of arrhythmia suppression is not needed, lower targets of suppression may be necessary. Lower drug dosages may improve the risk--benefit ratio of antiarrhythmic treatment.