During the last few decades our knowledge of transplantation has been remarkably expanded to the point where transplants are a standard treatment modality. However, despite the fact that certain tolerogenic protocols seemed to be very successful in small animal models, researchers anticipated the same outcomes in humans, which has mostly not been true yet. Immunological memory is known to be one of the reasons for such discrepancies. Donor-specific memory T cells are thought to be a crucial barrier in transplant success due to their unique properties. Recently, efforts to overcome this issue have been made, and several protocols showed the inhibition of memory T cell functions both in vitro and in vivo. In this review, we discuss the role of memory T cells in transplant rejection and the rising strategies to overcome this barrier.
Graft Rejection ; Humans ; Immune Tolerance ; Immunologic Memory ; Memory ; Models, Animal ; Rejection (Psychology) ; T-Lymphocytes ; Transplantation, Homologous ; Transplants

During virus infection, T cells must be adapted to activation and lineage differentiation states via metabolic reprogramming. Whereas effector CD8⁺ T cells preferentially use glycolysis for their rapid proliferation, memory CD8⁺ T cells utilize oxidative phosphorylation for their homeostatic maintenance. Particularly, enhanced AMP-activated protein kinase (AMPK) activity promotes the memory T cell response through different pathways. However, the level of AMPK activation required for optimal memory T cell differentiation remains unclear. A new metformin derivative, IM156, formerly known as HL156A, has been reported to ameliorate various types of fibrosis and inhibit in vitro and in vivo tumors by inducing AMPK activation more potently than metformin. Here, we evaluated the in vivo effects of IM156 on antigen-specific CD8⁺ T cells during their effector and memory differentiation after acute lymphocytic choriomeningitis virus infection. Unexpectedly, our results showed that in vivo treatment of IM156 exacerbated the memory differentiation of virus-specific CD8⁺ T cells, resulting in an increase in short-lived effector cells but decrease in memory precursor effector cells. Thus, IM156 treatment impaired the function of virus-specific memory CD8⁺ T cells, indicating that excessive AMPK activation weakens memory T cell differentiation, thereby suppressing recall immune responses. This study suggests that metabolic reprogramming of antigen-specific CD8⁺ T cells by regulating the AMPK pathway should be carefully performed and managed to improve the efficacy of T cell vaccine.
AMP-Activated Protein Kinases ; Cell Differentiation ; Fibrosis ; Glycolysis ; Immunologic Memory ; In Vitro Techniques ; Lymphocytic choriomeningitis virus ; Lymphocytic Choriomeningitis ; Memory ; Metformin ; Oxidative Phosphorylation ; T-Lymphocytes

PURPOSE: In the present study, the protective immunological markers in serum and peripheral blood mononuclear cells (PBMCs) of bacillus Calmette-Guerin (BCG) vaccinated and unvaccinated children were evaluated after vaccination. Further, PBMCs of children with low protective levels were boosted with BCG, Ag85B, and Ag85B peptides to study their booster effects to increase waning BCG induced immunity. MATERIALS AND METHODS: Fifty children from 1 month to 18 years of age were randomized for the study. Blood samples were collected from 27 participants with/without BCG vaccination. Immunological markers (anti-BCG, interferon gamma [IFN-gamma], and adenosine deaminase activity) were assessed in both serum and PBMCs of children. Children with low levels of protective immunological markers were further recruited and their PBMCs were boosted with BCG, Ag85B, and Ag85B peptides. RESULTS: Children in age group of 4-6 years were associated with significantly (p<0.05) higher BCG-specific IgG and IFN-gamma levels compared to those in age group greater than 10 years. Vaccinated children had greater repertoire of immunological memory which on in vitro stimulation with BCG showed increase in BCG-specific response compared to unvaccinated controls. Assessment of booster effects of BCG, Ag85B, and Ag85B peptides in PBMCs of children revealed greater potential of peptides to boost BCG induced immunity compared to BCG and Ag85B. CONCLUSION: To conclude, children within age 4-6 years are associated with high immunological markers which eventually diminish with age thereby suggesting need for booster dose in later years. Mycobacterium tuberculosis peptides along with BCG may be used as attractive candidates to boost such waning BCG induced immunity in children.
Adenosine Deaminase ; Bacillus ; BCG Vaccine ; Child* ; Humans ; Immunoglobulin G ; Immunologic Memory ; Interferon-gamma ; Interferons ; Mycobacterium bovis* ; Mycobacterium tuberculosis ; Peptides* ; Vaccination

OBJECTIVETo evaluate the immunity status on different hepatitis B vaccines currently being used in Beijing.

METHODSCollege students who had not received hepatitis B vaccine and children who had received whole-course immunization at birth, were tested HBsAg, anti-HBs and anti-HBc. All the test-negative cases were served as research subjects. 3 doses recombinant hepatitis B vaccines were given to the college students, following the 0, 1, 6 months schedule. Among which, 140 cases received recombinant beer yeast hepatitis B vaccine (BY vaccine, 10 microg, 5 microg, 5 microg), and 140 cases with recombinant hansenula polymorpha hepatitis B vaccine (HP vaccine, 10 microg, 10 microg, 10 microg). 1 dose was given for boosting immunization to 98 children, in which 49 cases with BY vaccine (5 microg) and 49 cases with HP vaccine (10 microg). Anti-HBs was tested 1 month after.

RESULTSThe total positive (> or = 10 mIU/ ml) rate was lower among BY vaccine group than HP vaccine group for the college students (93.5 %, 99.3% , P<0.05), but no statistical difference on GMT(81.2 mIU/ml, 94.6 mIU/ml, P>0.05) was found. For males, the positive rate and GMT were lower in BY vaccine group than in HP vaccine group (85.7% ,100.0%, P<0.01)(56.6 mIU/ml, 98.6 mIU/ml, P<0.01), but with no statistical difference for females (98.8%, 98.5%, P> 0.05) (103.4 mIU/ml, 90.3 mlU/ml, P> 0.05). For the same vaccine, the positive rate and GMT were lower in males than in females when using BY vaccine (85.7% , 98.8%, P<0.01)(56.6 mIU/ml,103.4 mIU/ml, P< 0.01), but no statistical difference was found on HP vaccine(100.0%, 98.5%, P>0.05)(98.6 mIU/ml, 90.3 mIU/ml, P>0.05). The positive rate of anti-HBs was decreasing along with age among the children who had received a whole-course immunization at birth (P <0.01). 98.6 % of the 70 negative cases appeared positive conversion after receiving 1 dose and the GMT raised significantly by 15 times. No statistical difference was found between the two kinds of vaccines(100.0%, 97.4%, P>0.05)(80.5 mIU/ml, 68.5 mIU/ml, P>0.05).

CONCLUSIONSThe type of vaccine and sex were related to the effects, better with HP vaccine than BY vaccine in males but was the same for females in adults receiving basic immunization according to the conventional doses. Both kinds of vaccines were ideal when children receiving boosting immunization. The immune memory was good for persons who had received primary immunization with recombinant vaccine but antibody appeared negative conversion. It was not necessary to boost immunization within 6 years after a whole-course immunization with recombinant hepatitis B vaccine in infancy.

Antibodies, Viral ; analysis ; China ; Female ; Hepatitis B Vaccines ; immunology ; Humans ; Immunization, Secondary ; Immunologic Memory ; Male ; Students ; Universities

OBJECTIVETo investigate the immunization status of hepatitis B vaccine who were inoculated at birth, HBV infections and the vaccine booster effect in the first-year middle school students (12 - 14 years old).

METHODSA cluster, stratified simplified random sampling method was administrated. The sample size was at least 218, which was calculated by Epi Info 3.3.2 software at 53% the minimum acceptable anti-HBs positive rate and 95% confidence level. A total of 250 and 236 students participated in the infection status and booster immunization effects investigation. The HBsAg, anti-HBs and anti-HBc IgG were detected by Enzyme-linked immunosorbent assay (ELISA). HBV DNA was detected by fluorescence quantitative PCR, and the diagnostic test kit were produced respectively by ABBOTT, Diasorin and Beijing Wantai Biological Pharmacy Enterprise Co.

RESULTSFor the immunization status before booster: the positive rate of anti-HBs was 62.80% (157/250), the GMT was 73.79 IU/L; the currently HBV infection rate (HBsAg and anti-HBc positive) was 2.80% (7/250). After injection, the anti-HBs positive rate was 94.92% (224/236). Compared with the before booster results, the significant difference was observed (χ(2) = 73.92, P = 0.00). The GMT was 521.15 IU/L, comparing with the before booster results, there was significant difference (t = 15.98, P = 0.00). The anti-HBs conversion rate (from negative to positive) was 91.86% (79/86) after immune-enhancement; of which, 11 students got the second dose of booster vaccine who are no-responders after first injection, in addition 8 students got the anti-HBs.

CONCLUSIONIt is an effective method to put the first-year middle school students into the immune-enhancement program, so as to improve the immunization memory effect and avoid the loss of protective antibodies.

Adolescent ; Child ; China ; Dose-Response Relationship, Immunologic ; Female ; Hepatitis B ; immunology ; prevention & control ; Hepatitis B Antibodies ; immunology ; Hepatitis B Vaccines ; administration & dosage ; immunology ; Humans ; Immunization, Secondary ; Immunologic Memory ; immunology ; Male ; Schools ; Students

PURPOSE: This study was conducted to assess the current(2003-2005) prevalence of anti-HBs and immunologic memory for Hepatitis B vaccine in children from the central area of Korea. METHODS: Subjects were chosen from children and adolescents who received tests for hepatitis B surface antigen(HBsAg) and anti-HBs at Dankook University Hospital from March 2003 to May 2005. Among these, antibodies to hepatitis B core antigen(IgG anti-HBc) were checked. A single booster vaccination was performed on children whose anti-HBs titers were under 10 mIU/mL. One month after booster vaccination we rechecked the anti-HBs titer. RESULTS: A total of 3,277 subjects were tested for HBsAg/anti-HBs, and 1,913(58.4 percent) of them were positive for anti-HBs. Of these, 29 subjects(0.9 percent) were positive for HBsAg. Positive results for anti-HBs by age were 78.6 percent for 6-12 months of age, 62.7 percent for 1-3 years of age, 51.9 percent for 4-6 years of age, 49.5 percent for 7-12 years of age, 63.4 percent for 13-15 years of age and 72.2 percent for 16-18 years of age. The 80 subjects who were tested negative for HBsAg/anti-HBs received a single booster vaccine, 71 subjects were tested positive for antibodies. IgG anti-HBc titer was checked for 169 of the subjects, 5 subjects were positive. CONCLUSION: In our study, a significant anamnestic response was observed in 88.8 percent of children. This is believed to be a result of the relatively long immunologic memory effect of the hepatitis B vaccination in children from the central area of Korea.
Adolescent ; Antibodies ; Child* ; Hepatitis B Surface Antigens ; Hepatitis B Vaccines* ; Hepatitis B* ; Hepatitis* ; Humans ; Immunoglobulin G ; Immunologic Memory* ; Korea* ; Prevalence* ; Vaccination

Streptococcus pneumoniae causes considerable morbidity and mortality. There are currently two types of pneumococcal vaccine available under license: pneumococcal polysaccharide vaccines(PPV23) and pneumococcal conjugate vaccines(PCV-7). PPV23 contains T-cell independent antigens which stimulate mature B lymphocytes and produce an effective antibody response. However T-lymphocytes are not involved which leads to an absence of immunological memory and lack of an anamnestic response on challenge. The 23-valent vaccine is reported to be effective in older children and adults, and is currently recommended for high-risk patients such as hyposplenic patients and the general elderly population. PPV23 appears cost effective for elderly patients PCV-7 has high efficacy against radiological pneumonia and invasive pneumococcal disease, acute otitis media, reduces the nasopharyngeal colonization rate of vaccine strain, and provides herd immunity. PCV-7 may also provide an effective new tool to reduce disease caused by drug-resistant strains of pneumococci. But this vaccine has limited serotype coverage, replacement phenomena. It remains unknown if long-term serotype shifts would be caused by PCV-7. And the possibility of the spread and acquisition of virulent non-vaccine serotypes is a real threat which must be monitored. New PCVs including more serotypes could prove to be good options in the future for all age groups. Several protein-based pneumococcal vaccine candidates (currently under investigation in animal models) offer the potential advantage of serotype independent protection in the near future.
Acute Disease ; Adult ; Aged ; Animals ; Antibody Formation ; B-Lymphocytes ; Child ; Colon ; Humans ; Imidazoles ; Immunity, Herd ; Immunologic Memory ; Nitro Compounds ; Otitis Media ; Pneumococcal Vaccines ; Pneumonia ; Sprains and Strains ; T-Lymphocytes

OBJECTIVETo study the immune memory in vaccinees after the completion of a full schedule hepatitis B immunization.

METHODSOne thousand and two hundred one infants born in 1987 -1989 were immunized with 3 doses of plasma derived hepatitis B vaccine, while 2484 newborn babies during 1996-1999 were injected with 3 doses of the yeast recombinant hepatitis B vaccine. All of the infants under observation were tested for HBsAg, anti-HBs and anti-HBc, in 2005. Of 959 individuals negative for anti-HBs (< 10 mIU/ml), HBsAg and anti-HBc, 228 were immunized with plasma-derived vaccine and 731 with yeast recombinant vaccine after birth. All of them were detected for anti-HBs 15 days after a booster of 10 Ipg yeast recombinant vaccine. In addition, interleukin-2 (IL-2) was detected in 11 non-responders and 22 responders after boostering, using an enzyme-linked immunospot (ELISPOT). The anti-HBs levels of 190 individuals (91 with plasma derived vaccine and 99 with yeast recombinant vaccine) who had had quantitative data on their antibody status after the primary hepatitis B vaccination, were compared with that after the boostering.

RESULTSAmong the individuals who received plasma derived vaccine 16-18 years ago, 79.82% of them showed the signs of immune memory after one booster, with a geometric mean titer (GMT)of 325.69 mIU/ml. Of the individuals who received the yeast recombinant vaccine 6-9 years ago, 95.62% showed immune memory after one booster,with its GMT of 745.18 mIU/ml. Anti-HBs levels induced by the booster were associated with that after the primary immunization. The positive rate of IL-2 was 40.91% in subjects with good immune memory. However, IL-2 was not detected in non-responders after the booster (P < 0.01).

CONCLUSIONMost of the individuals who had received a completed schedule of primary hepatitis B vaccination and seroconverted from anti-HBs positive to negative,showed the signs of having immune memory after the booster. Only a small proportion of the vaccinees had lost their immune memory during the long term follow-up period, suggesting that these individuals should receive a booster of hepatitis B vaccine in the highly endemic areas of hepatitis B. Hepatitis B virus; Immune memory; Booster immunization

Antibody Formation ; Hepatitis B ; immunology ; prevention & control ; Hepatitis B Vaccines ; administration & dosage ; immunology ; Humans ; Immunization, Secondary ; Immunologic Memory ; Infant ; Infant, Newborn ; Interleukin-2 ; blood

OBJECTIVEThe aim of the study was to evaluate the anti-HBs persistence and the long term preventive efficacy after vaccination 23 years with plasma-derived hepatitis B vaccine.

METHODSThe study consisted of 261 children who were 5 - 9 years aged, from two primary schools in two townships of Xi'an. 126 children were randomly selected as vaccine group, and 135 children in control group. These children were followed up again in 2009. Excluding self-inoculation, the vaccine and control groups were 81 and 75, who was used to ask to recall details of their experience for vaccination and liver-related illnesses during past twelve years. Individuals who had anti-HBs titers less 10 mIU/ml, HBsAg, anti-HBc and HBV-DNA all were negative, were given a booster dose vaccine and retest for anti-HBs titer after one month.

RESULTSAfter eliminated the interference of an early booster dose and vaccination outside the study, the positive rate of anti-HBs was 48.1% (39/81) in the vaccine group at year 23, higher than 34.7% (26/75) in control group. At year 23 after primary vaccination, 84.0% (21/25) individuals in the vaccine group whose anti-HBs and anti-HBc both are negative showed a stronger anamnestic response after received a booster dose, while 7.5% (3/40) in the control group. At year 23 after primary vaccination, none clinical case of hepatitis B was found among 194 individuals. However, anti-HBc positive rate in the vaccine group was 16.0% (13/81), while the rate in the control group was 30.7% (23/75) (χ(2) = 4.687, P < 0.05).

CONCLUSIONAt 23 years after implemented a full course of plasma-derived hepatitis B vaccine, the recipients of vaccine were maintained anti-HBs at a high level or strong immunological memory.

Child ; Child, Preschool ; Follow-Up Studies ; Hepatitis B ; immunology ; prevention & control ; Hepatitis B Antibodies ; blood ; Hepatitis B Vaccines ; immunology ; Humans ; Immunization, Secondary ; Immunologic Memory ; immunology ; Plasma ; immunology

The germinal center reaction is a key event of humoral immunity, providing long-lived immunological memory. Follicular helper T (T(FH)) cells are a specialized subset of CD4⁺ T cells located in the follicles, which help B cells and thus control the germinal center reaction. T(FH) cell development is achieved by multi-step processes of interactions with dendritic cells and B cells along with the coordination of various transcription factors. Since the T helper cell fate decision program is determined by subtle changes in regulatory molecules, fine tuning of these dynamic interactions is crucial for the generation functional T(FH) cells. MicroRNAs (miRNAs) have emerged as important post-transcriptional regulatory molecules for gene expression, which consequently modulate diverse biological functions. In the last decade, the miRNA-mediated regulation network for the germinal center reaction has been extensively explored in T cells and B cells, resulting in the identification of several key miRNA species and their target genes. Here, we review the current knowledge of the miRNA-mediated control of the germinal center reaction, focusing on the aspect of T cell regulation in particular. In addition, we highlight the most important issues related to defining the functional target genes of the relevant miRNAs. We believe that the studies that uncover the miRNA-mediated regulatory axis of T(FH) cell generation and functions by defining their functional target genes might provide additional opportunities to understand germinal center reactions.
B-Lymphocytes ; Dendritic Cells ; Gene Expression ; Germinal Center ; Immunity, Humoral ; Immunologic Memory ; MicroRNAs ; T-Lymphocytes ; T-Lymphocytes, Helper-Inducer* ; Transcription Factors