人和动物布氏菌病血清IgG抗体的固相放射免疫分析法及其应用的研究——Ⅰ 检测布病病人和奶牛血清IgG抗体的固相放射免疫分析法(SPRIA)

本文报道,应用~(125)I—SPA为结合剂建立一种间接固相放射免疫分析法(SPRIA),可以同时检测布氏菌病病人和病牛血清的布氏菌IgG抗体。对于其IgG同SPA结合力很差的犊牛血清IgG抗体的检测,只需在加入~(125)I—SPA之前,先加入1:100的兔抗牛血清即可完成。如用於布病病牛血清抗体的检测,灵敏度更高,而用於病人血清的检测,结果同SPRIA一致。方法学检验结果证明,SPRIA和双抗体SPRIA均有良好的特异性、灵敏度和重复性,效果优於CFT、SAT和ELISA,而且方法简便快速,一天即可完成测定。方法对於人、畜布病的血清学诊断和实验研究,具有较为广泛的适应性。     

辛酸-硫酸铵法在纯化血清旋毛虫特异性IgG抗体中的应用

目的 从旋毛虫感染的大鼠和兔血清中纯化抗旋毛虫IgG抗体. 方法 分别用辛酸-硫酸铵法(CA-AS)、硫酸铵沉淀法(AS)纯化旋毛虫感染的大鼠和兔血清中抗旋毛虫IgG抗体. 结果 IgG抗体纯化率CA-AS法为80.05%～83.22%,AS法为67.00%～71.08%;得率CA-AS法为7.85～8.79 mg/ml,AS法为12.04～12.12 mg/ml;回收率CA-AS法为52.55%～55.03%,AS法为61.36%～64.87%.CA-AS法得率和回收率均低于AS法,但纯化率高于AS法.ELISA法测定CA-AS法和AS法纯化的抗体效价不变. 结论 CA-AS法是一种简便﹑快速﹑有效的纯化血清IgG抗体的方法,可用于大鼠和兔血清抗旋毛虫IgG抗体的纯化.     

基于OMP18的B细胞抗原表位的空肠弯曲菌ELISA检测方法的建立

目的 以OMP18的B细胞抗原表位多肽为包被抗原,建立检测空肠弯曲菌感染的ELISA方法。方法 以不同浓度梯度(0.1,1,10 μg/mL)OMP18的B细胞抗原表位多肽进行包被,以空肠弯曲菌全菌兔抗IgG为一抗,HRP标记的羊抗兔抗体IgG为二抗,检测对原浓度1 mg/mL的不同稀释度(1:10,1:100,1:1 000)抗体IgG水平。分别以空肠弯曲菌感染兔血清、健康兔血清及沙门菌感染兔血清为一抗,1:3 000稀释的HRP标记的羊抗兔IgG为二抗,比较各抗原表位多肽的免疫特异性。结果 OMP18的B细胞抗原3个表位多肽在稀释度在1:1 000、1:4 000、1:16 000、1:64 000时免疫反应性均有明显增高。其中稀释度在1:1 000时增高最明显。OMP18的B细胞抗原表位多肽具有免疫特异性。结论 用OMP18的B细胞抗原表位多肽作为包被抗原对空肠弯曲菌感染的血清进行ELISA检测,免疫反应性高,具有免疫特异性。     

日本血吸虫病经胎盘传播免疫耐受性的进一步研究

目的进一步探索日本血吸虫病经胎盘传播的免疫耐受性.方法对不同孕期的怀孕母兔分别感染300条日本血吸虫尾蚴,感染45天后收集母兔和仔兔血清84份,在检测家兔日本血吸虫特异性IgG抗体研究结果的基础上,进一步以ELISA方法检测日本血吸虫特异性IgM抗体.结果10份母兔血清IgM抗体检测均为阳性(OD=0.82～1.51),74份仔兔血清均为阴性(OD=0.01～0.49);怀孕中期感染日本血吸虫母兔所产仔兔(52份)和怀孕晚期感染所产仔兔(22份)血清,OD均值分别为0.23和0.28,两者差异有显著意义(P＜0.05);同一怀孕期感染日本血吸虫母兔所产仔兔血清,OD值差异无显著意义(P＞0.05).结论日本血吸虫经胎盘传播后,所产仔兔在短期内产生免疫耐受性.     

弓形体抗原的免疫化学研究

本文应用4种免疫血清学方法和免疫印迹技术分析了3种不同毒力弓形体株(RH、Beverley和Fukaya)感染小鼠后诱导血清IgM和IgG抗体产生的速殖子表膜抗原及株间的抗原差异。速殖子膜有3种主要功能性抗原,分子量分别为120、35和27kd。P_(27)除被IgG抗体识别外,同时还可被IgM抗体所识别。用SDS-聚丙烯酰胺凝胶电泳(SDS-PAGE)分离并部分纯化的抗原进行ELISA检测发现,含有P_(35)的洗脱抗原组分与小鼠多克隆抗体反应最为强烈,其次为含有P_(27)的洗脱组分。用洗脱各抗原组分免疫小鼠后证明,血清IgG抗体主要与P_(35)和P_(27)结合。用部分纯化的P_(35)抗原免疫小鼠可使受试鼠获得抗攻击感染的部分保护性免疫力。     

鼠疫菌感染兔血清抗体谱分析

目的分析鼠疫耶尔森菌感染的兔血清(鼠疫菌感染兔血清)中抗体产生的种类与规律,为了解鼠疫菌的致病机制及筛选新的疫苗亚单位提供实验依据。方法利用含有145个鼠疫菌毒力相关蛋白的蛋白质芯片检测鼠疫菌感染兔血清抗体谱,并与鼠疫菌活疫苗EV76株免疫兔血清(免疫兔血清)抗体谱比较。结果在鼠疫菌感染兔血清中共检测到41个蛋白相应的抗体,其中28个抗体在免疫兔血清中也检测到,有6个蛋白抗体只在鼠疫菌感染兔血清中检测到。结论鼠疫菌感染兔血清的抗体谱与免疫兔血清的抗体谱不完全一致,通过对鼠疫菌感染兔血清抗体谱的研究,可为深入了解细菌的致病机制及筛选新的疫苗亚单位奠定基础。     

用免疫荧光法鉴定日本血吸虫成虫表皮、肠道、虫卵及尾蚴的抗原

在家兔感染日本血吸虫过程的追踪研究中用间接荧光抗体试验分析日本血吸虫抗原的定位,或许由于成虫、虫卵和尾蚴存在共同抗原,故难于说明感染过程中抗原的期特异性。本研究用不同剂量干重的日本血吸虫雄虫、雌虫、虫卵抗原及肝片吸虫、华支睾吸虫、菲律宾肺吸虫的盐水提取粗制抗原和福氏完全佐剂一起分4次皮内免疫家兔,每周1次,第5次为强化剂,不加佐剂。2周后收集血清,然后通过铵盐沉淀及DEAE纤维素柱层析分离和纯化抗日本血吸虫成虫及虫卵的IgG,并用异硫氰基荧光素标记(即FITC-Ad-IgG和FITC-Egg-IgG)。日本血吸虫成虫、虫卵、尾蚴的组织切片分别用冰丙酮及福尔马林固定以用作荧光试验的抗原。间接荧光法用不同稀释度的免疫兔血清与抗原切片孵育,然后用荧光标记的抗兔γ-球蛋白检测,直接荧光试验用FITC-Ad-IgG及FI-TC-Egg-IgG检测,免疫荧光抑制试验,则用     

旋毛虫成虫排泄分泌抗原检测唾液中抗旋毛虫IgG抗体的研究

目的 评价旋毛虫(Trichinella spiralis)成虫排泄分泌抗原(adult worm excretory-secretory antigen,AWESA)作为诊断抗原检测旋毛虫感染日本大耳兔唾液中抗旋毛虫IgG抗体的可行性. 方法 建立旋毛虫感染日本大耳兔和对照组兔动物模型,采集感染前和感染后1～6周兔唾液和血清以及对照组兔唾液和血清.制备AWESA,建立AWESA作为诊断抗原的间接酶联免疫吸附试验(enzyme-linked immunosorbent assay,ELISA),以市售旋毛虫IgG抗体检测试剂盒作为对照,测定感染前和感染后1～6周兔唾液和血清以及对照组兔唾液和血清中抗旋毛虫IgG抗体.AWESA和试剂盒测得的唾液A值和血清A值进行线性相关分析,AWESA和试剂盒测得的唾液阳性率和血清阳性率分别进行x2检验.结果 AWESA检测唾液和血清特异性IgG抗体阳性率依次为0、5%、20%、40%、60%、85%、90%,0、30%、60%、85%、95%、100%、100%,除感染后0、1、2周外其余各周唾液A值与血清A值呈显著线性相关(P＞0.05、P＞0.05、P＞0.05、P＜0.05、P＜0.05、P＜0.05、P＜0.05).市售旋毛虫IgG抗体检测试剂盒检测旋毛虫感染前和感染后兔唾液和血清中特异性IgG抗体阳性率依次为0、15%、20%、40%、55%、75%、90%,0、35%、60%、95%、95%、100%、100%,除0、1、3周外其余各周唾液A值与血清A值呈线性相关(P＞0.05、P＞0.05、P＜0.05、P＞0.05、P＜0.05、P＜0.05、P＜0.05). 结论 AWESA与市售试剂盒检测唾液和血清中抗旋毛虫IgG抗体的阳性率具有一致性.     

先天性感染日本血吸虫家兔攻击感染后血清抗体动态的进一步研究

目的运用日本血吸虫成虫抗原和虫卵抗原检测日本血吸虫先天性感染仔兔攻击感染后的血清特异性IgG、IgM抗体并观察其动态变化,探讨仔兔先天性感染后的体液免疫应答.方法10只怀孕晚期母兔分为三组:4只孕兔人工感染700条日本血吸虫尾蚴/只,所产仔兔为先天性感染组(G1);3只孕兔人工感染700条日本血吸虫尾蚴/只,所产仔兔于出生后第55天攻击感染20条尾蚴/只,该组仔兔为先天性感染且攻击感染组(G2);3只孕兔不感染,正常分娩的健康同龄仔兔感染20条尾蚴/只作对照C组.三组仔兔分别于出生后第53、67、81、95天采血收集血清,分别运用AWA-ELISA及SEA-ELISA法检测血清特异性IgG、IgM抗体,观察动态变化.结果仔兔先天性感染率为66.7%(10/15);G2组和G1组10只先天性感染仔兔相比较,血清特异性IgG、IgM抗体动态规律均比较接近,无论是AWA-ELISA还是SEA-ELISA检测,出生后第95天仔兔IgG、IgM抗体0D均值在两组间差异均没有显著性(P＞0.05);对照组仔兔血清IgG、IgM出生后第95天检测几乎全部呈阳性,抗体阳性仔兔数明显多于同期G1、G2组,且0D均值也显著高于同期G1、G2组(P＜0.05).结论先天性感染日本血吸虫的仔兔血清抗体呈低免疫反应状态(hypo-responsiveness),可能存在免疫耐受,攻击性感染不能诱导仔兔免疫系统产生明显的保护性免疫.     

检测鼠疫抗体胶体金免疫层析试纸条的研制

目的建立快速、简易的检测鼠疫F1抗体的胶体金免疫层析法(G ICA)。方法(1)采用胶体金颗粒标记纯化F1抗原,并将标记物喷于玻璃纤维;同时将纯化F1抗原喷线固定于硝酸纤维素膜上,用于F1抗体的捕捉;按常规组装成检测鼠疫抗体免疫层析试纸条。(2)采用该试纸条与血凝法对同一份兔抗F1抗体进行检测,以评价该试纸条的敏感性。(3)采用该试纸条对44株非鼠疫菌的免疫鼠血清进行检测,以评价该试纸条的特异性。(4)采用该试纸条、血凝法及ELISA对607份血清标本进行检测,以评价该试纸条对现场材料的检测效果。结果(1)该试纸条可在15 m in之内完成检测;(2)在敏感性上,该试纸条对同一份免疫兔血清的检测较血凝法高一个滴度;(3)对被试的44株所选菌株的免疫鼠血清的检测均为阴性;(4)在对607份血清标本的检测中,免疫层析试纸条、血凝及ELISA三种方法的符合率中度,而免疫层析试纸条的敏感性分别比血凝与ELISA高111%和90%。结论以纯化的鼠疫F1抗原为基础建立的G ICA检测鼠疫F1抗体的方法特异性强、灵敏度高、简便快速,无需特殊仪器设备,有较大的推广应用价值。     

日本血吸虫重组线粒体相关蛋白免疫学活性鉴定

分子筛进一步纯化并复性的融合蛋白均能刺激家兔产生特异性抗体 ,粗提包涵体蛋白免疫家兔 ,血清抗体滴度为 1∶2 5 6 0 0 ,复性蛋白及经分子筛纯化的蛋白免疫的家兔血清抗体滴度均为 1∶5 12 0 0 ,Westernblot结果显示 ,粗提包涵体蛋白、复性蛋白及经过分子筛进一步纯化并复性的蛋白均能被重感染兔血清和rSj338/2 6GST特异性免疫兔血清所识别。攻击实验中 ,粗提包涵体蛋白和经分子筛纯化的蛋白分别可诱导小鼠产生 2 7.8% (P <0 .0 1)和 30 .4 % (P <0 .0 1)的减虫率 ,4 0 .4 % (P <0 .0 1)和 4 3.5 % (P <0 .0 1)肝总减卵率。粗提包涵体蛋白中rSj338和经分子筛纯化的蛋白中rSj338分别可诱导小鼠产生 13.9% (P <0 .0 5 )和 2 0 .0 % (P <0 .0 5 )的减虫率 ,30 .0 % (P <0 .0 1)和 4 1.7% (P <0 .0 1)肝总减卵率。结论　获得的日本血吸虫线粒体相关的重组融合蛋白(rSj338/2 6GST)具有良好的免疫学活性 ,重组融合蛋白 (rSj338/2 6GST)及rSj338均可诱导宿主抗血吸虫感染的部分保护力。     

A族链球菌表面蛋白Fba的原核表达及免疫原性分析

目的 研究A族链球菌(GAS)表面新型纤连蛋白Fba的免疫原性,探讨GAS感染机体的免疫应答机制.方法 PCR扩增fba基因,测序正确后克隆至原核表达质粒pGEX4T-2,并在E.coli BL21中表达,应用ELISA和Western印迹法鉴定目的 蛋白表达,以该蛋白作为抗原,包被酶联板,检测GAS全菌免疫鼠血清、33份抗链球菌"O"阳性患者血清.同时,将该蛋白免疫Balb/C小鼠,3次免疫后收集皿清,检测IgG效价.结果 ELISA和Western印迹证实,表达的Fba重组蛋白可与已知兔抗Fba阳性血清产生特异性反应;且Fba蛋白可与GAS全菌免疫鼠血清、抗链球菌"O"阳性患者血清发生特异性结合.Fba蛋白免疫小鼠后抗血清IgG效价达1:4800.结论 GAS感染或Fba蛋白免疫动物后均可诱导动物体产生Fba抗体,该抗体与Fba重组蛋白可产生特异性反应,提示Fba蛋白具有良好的免疫原性和抗原性.Fba蛋白可作为GAS的候选疫苗及检测GAS感染患者血清效价的重要工具.     

Impaired immune responsiveness in Plasmodium berghei immune mice

Mice immunized against Plasmodium berghei parasites by drug-controlled infection exhibited decreased immunoresponsiveness against rabbit red blood cells (RRBC). Increasing RRBC antigen dose increased responsiveness, but agglutinating anti-RRBC antibodies of the IgG class remained undetectable. Clearance of colloidal carbon from the bloodstream of malaria-immunized mice was not different from controls. Removal of all the persistent parasites from immune mice did not restore responsiveness until 140 days after treatment, suggesting that the parasite per se did not influence responsiveness directly. Because of this, and because of the fact that priming of mice with RRBC before P. berghei immunization was not more effective than priming after immunization, it was concluded that antigen uptake and subsequent presentation were not impaired in P. berghei immune mice, in contrast to infected mice. Anti-RRBC antibodies were detected in serum of P. berghei immune mice, but regulation of responsiveness to RRBC by transfer of such immune mouse serum was not found. Immunoglobulin levels, especially of the IgG2 and IgG3 subclass were elevated in sera of P. berghei immune mice, which indicated an LPS-like polyclonal activation. The results also suggest that during drug-controlled infection, which leads to immunity against infection, a state of B-cell tolerance is induced.     

The specificity of antibodies to the F(ab')2 fragment of human IgG

The specificity of IgG anti-F(ab')2 antibodies was examined by unfractionated sera of patients with rheumatoid arthritis and also with affinity-purified antibody preparations. Examination of the sera by an enzyme-linked immunosorbent assay, using pooled human F(ab')2 fragments absorbed to microtiter plates, revealed that IgG anti-F(ab')2 antibodies cross-react with human and rabbit IgG and rabbit F(ab')2. IgG anti-F(ab')2 antibodies were purified by affinity chromatography and, when tested by a fluid-phase inhibition enzyme-linked immunosorbent assay, were found to be of 2 types. One fraction, similar to pepsin agglutinator, reacted with human F(ab')2 fragment alone. The other fraction was cross-reactive with human IgG and yet failed to react with idiotopes on Fab or epitopes on Fc fragments. The IgG anti-F(ab')2 antibodies we purified had no reactivity toward a human immune complex prepared from tetanus toxoid and antitoxoid.     

东方田鼠血清IgG抗体的快速纯化法

目的　探索快速、高效纯化东方田鼠血清IgG抗体的方法。　方法　采用G蛋白或A蛋白亲和层析法,对3种东方田鼠血清IgG抗体进行纯化,比较抗体纯度和回收率。　结果　获得的IgG抗体纯度和回收率均以G蛋白亲和层析法为高。纯化的抗体活性高,与酶标二抗的吸附力分别为非IgG洗脱物的8.5倍和未纯化血清IgG的3.1倍。　结论　G蛋白亲和层析法纯化东方田鼠血清IgG快速、活性高,具有实用价值。     

Restricted neutralization of divergent human T-lymphotropic virus type III isolates by antibodies to the major envelope glycoprotein.

By analogy to other retroviruses, the major envelope glycoprotein, gp120, of human T-lymphotropic virus type III (HTLV-III) is a probable target for neutralizing antibody. This antigen has been purified from H9 cells chronically infected with the HTLV-IIIB prototype strain. Several goats immunized with the gp120 produced antibodies that neutralized infection of H9 cells by the homologous virus isolate. These same sera failed to neutralize the divergent HTLV-IIIRF isolate. Individuals infected with HTLV-III commonly develop antibodies to gp120 that could be isolated by using the gp120 antigen coupled to an immunoadsorbent resin. The antibody fraction that bound tightly to such a resin was found to neutralize the IIIB but not the RF isolate in a similar fashion as the goat anti-gp120 sera. However, the nonbinding fraction (effluent) from the resin also contained neutralizing activity that was able to block infection by both virus isolates with similar efficacy. Human antibodies to the other virus envelope gene product, the transmembrane gp41, were also affinity purified by utilizing the recombinant peptide 121, but these failed to influence infection by either virus isolate.     

Analysis of immune responses against H pylori in rabbits

AIM： To investigate the immunogenicity of H pylori proteins, to evaluate the production rate of anti H pylori IgG antibodies in relation to time and to demonstrate the fidelity of newly optimized in-house enzymelinked immunosorbent assay （ELISA） technique as an alternative for H pylori infection assay.
METHODS： In the present study, 100 μg of formalinfixed H pylori whole cell antigens was injected into an experimental animal （New Zealand white female rabbit） intramuscularly on d 0, 16, 27 and 35. The first two doses were injected with adjuvants. On d 0, a serum sample was collected from the rabbit before immunization and this pre-immunized serum was used as a negative control for the whole study. To evaluate the immunogenic responses of the injected antigen, serum samples were collected from the rabbit at regular intervals up to d 42. The sera were analyzed using inhouse ELISA and Western blot techniques.
RESULTS： The production of anti Hpylor/IgG antibodies in the rabbit in response to the injected antigen increased almost exponentially up to d 14 and after that it was maintained at the same level until the last day （d 42）. By analyzing the immune profiles of immunized sera, 11 proteins were identified to be immunogenic, among them 2 （approximately 100 kDa and 85 kDa） were most prominent.
CONCLUSION： Analysis of the immune responses against pathogenic microorganisms like H py/ori is necessary for the development of various diagnostic and preventive approaches. The results of this experiment reveal that the formalin-fixed H pylori whole cell antigens injected into the rabbit are highly immunogenic. These prominent proteins （approximately 100 kDa and 85 kDa） might have higher immunogenic effects among humans infected with H pylori and some of these immunogenic proteins can be included in diagnostic approaches based on serology and also for vaccine formulation. The in- house ELISA is a promising alternative compared to invasive techniques.     

Lack of interspecies barriers in anti–Id stimulated antibody production against Echinococcus granulosus antigens

Polyclonal human anti-hydatid antibodies were affinity purified from a hydatid patient serum and used to produce a rabbit anti-idiotypic serum. These anti-Id antibodies cross-reacted in ELISA with sera from 11 of 12 hydatid patients studied and with 13 infected or immunized mice sera. All mice primed and boosted with anti-Id produced anti-hydatid antibodies in the primary response and exhibited an increase in antibody titre after a booster injection. The same effect was observed with mice primed with antigen and boosted with anti-Id, although these mice exhibited higher antibody titres. A significant idiotype repertoire is shared by anti-hydatid antibodies produced by different individuals of the same or different species, and anti-Id raised against those antibodies behave as surrogate antigens producing a normal primary and secondary response in animals of different species from that used to isolate the Id.     

BALB/c小鼠感染日本血吸虫后血清中SEA特异性抗体的动态观察

目的 观察BALB/c小鼠感染日本血吸虫后18周内血清中可溶性虫卵抗原 （SEA） 特异性IgG、 IgM抗体水平的动态变化。方法 尾蚴感染BALB/c小鼠, 感染2周后开始每周采血并分离血清, 以SEA为抗原, 通过ELISA测定不同感染时间血清IgG、 IgM值; 通过免疫印迹法检测不同感染时间小鼠血清中SEA特异性IgG、 IgM抗体条带。结果 ELISA检测结果表明感染小鼠血清IgG水平在感染5、 6、 9、 11周上升明显; IgM在感染5周和9周时上升明显。免疫印迹试验结果表明感染血吸虫4周后, 小鼠血清中开始出现140、 180、 210 kDa蛋白特异性IgG抗体; 感染5周后出现43、 50 kDa强反应IgG特异性抗体带; 感染6周后在60～130 kDa处出现 IgG特异性弥散带; 感染9周后出现38、 73 kDa 蛋白特异性IgG条带, 其中38 kDa 条带较弱, 随感染时间延长, 条带反应逐渐增强, 直至感染18周; 感染11周后新增26、 32、 35、 80 kDa特异性IgG条带, 并且在12周后增强。感染3周后出现100、 140、 180 kDa IgM特异性反应条带, 感染9周后出现73 kDa特异性IgM强反应条带及 38、 43、 50 kDa弱反应IgM抗体带, 后3条蛋白条带随感染时间延长逐渐变强。 结论 SEA中不同组分抗原对感染宿主的免疫调节具有时间特异性, 其中43、 50、 100、 140、 180 kDa具有早期诊断价值; 73 kDa 既可用于急性血吸虫病诊断, 也可用于慢性血吸虫病诊断; 28、 32、 35、 38、 80 kDa抗原既可作为慢性血吸虫感染的优势抗原, 同时也可能具有一定的抗血吸虫感染作用, 可作为疫苗开发的候选抗原。     

Antibodies to actin in autoimmune neutropenia

In an effort to characterize the cellular antigens recognized by anti-neutrophil antibodies in autoimmune neutropenia, we studied sera, purified immunoglobulin G (IgG) and isolated F(ab')2 from 70 neutropenic patients suspected of this diagnosis. Anti-neutrophil antibodies were found in the sera of 36 of these patients by either 125I-staph A binding or immunofluorescence cytometric techniques that detected increased binding of patients' IgG to normal neutrophils. Anti-neutrophil antibody positive sera were then evaluated for specific binding to electrophoretically separated neutrophil membrane-associated proteins by immunoblotting. A 43-Kd protein was consistently identified by eight anti-neutrophil antibody positive sera. The specificity of binding to this protein was confirmed with affinity purified IgG and F(ab')2 fragments prepared from these sera. Sera from 20 healthy normal controls and from 22 non-neutropenic, anti-neutrophil antibody negative rheumatoid arthritis patients failed to bind this protein. Separate studies identified the 43-Kd protein as actin. Purified Acanthamoeba actin comigrated with the protein and was specifically bound by anti-neutrophil antibody positive IgG. Moreover, two actin-specific monoclonal antibodies bound to the 43-Kd membrane-associated protein in immunoblots. In addition, a rabbit anti-actin antiserum not only bound to this same 43-Kd protein but also expressed anti-neutrophil antibody activity against normal human neutrophils, as did purified human anti-actin IgG prepared by affinity chromatography from the serum of one of the index patients. These studies indicate that the anti-neutrophil antibodies of certain patients with autoimmune neutropenia include autoantibodies specific for actin. The molecules on the surface of neutrophils, which have actin-like antigenic epitopes and are recognized by these anti-actin antibodies, remain to be characterized.